Work 3 rectilinear uniformly accelerated motion option 2. Independent work "Rectilinear uniformly accelerated motion" (Grade 9). Didactic in physics for ninth graders and solutions for them

Independent work in physics Rectilinear uniformly accelerated motion. Acceleration grade 9 with answers. Independent work includes 2 options, each with 3 tasks.

Option 1

1. The sled rolled off the snowy hill with uniform acceleration. Their speed at the end of the descent is 12 m/s. Descent time 6 s. With what acceleration did the movement occur if the descent began from a state of rest?

2. A skier slides down a hill moving in a straight line and with uniform acceleration. During the descent, the skier's speed increased by 7.5 m/s. Skier acceleration 0.5 m/s 2 . How long is the descent?

3. A motorcycle, starting off, moves with an acceleration of 3 m / s 2. What is the speed of the motorcycle after 4 seconds?

Option 2

1. The sled rolled down one hill and drove up another. During the ascent to the hill, the speed of the sledge, moving in a straight line and uniformly accelerated, changed from 12 m/s to 2 m/s in 4 s. Determine the acceleration modulus.

2. How long will it take for a car moving with an acceleration of 1.6 m/s 2 to increase its speed from 11 m/s to 19 m/s?

3. A skier starts downhill at a speed of 4 m/s. Descent time 30 s. The acceleration of the skier during the descent is constant and equal to 0.5 m / s 2. What is the speed of the skier at the end of the descent?

Answers to independent work in physics Rectilinear uniformly accelerated motion. Acceleration Grade 9
Option 1
1. 2 m/s 2
2. 15 s
3. 12 m/s
Option 2
1. 2.5 m/s 2
2.5 s
3. 19 m/s

Examination No. 2: “Rectilinear uniformly accelerated

motion"

Option number 1 K-Mech.2

https://pandia.ru/text/78/602/images/image002_24.jpg" align="left" width="154" height="122 src="> 1. The kayak covered a distance of 1000 m from start to finish with at a speed of 5 m/s and after passing the finish line it began to slow down with a constant acceleration of 0.5 m/s 2. How far from the start line will the kayak be 10 s after passing the finish line?

2. According to the acceleration graph shown in the figure, describe the movement of the body for 9 s, if v 0 = 0.

3. What speed are we talking about in the following example: the speed of the hammer when it hits the nail is 8 m/s.

4. A skier descends a mountain 100 m long. How long will the descent take if the acceleration is 0.5 m/s2?

Option number 4 K-Mech.2

https://pandia.ru/text/78/602/images/image004_18.jpg" align="left" width="83" height="30 src="> 2. The body motion equation is x = 128 + 12t – 4t 2. Construct graphs of the speed and acceleration of the body. Determine after what period of time the body will stop.

4. Car after uniform motion switched to accelerated. And moving with an acceleration of 1.5 m / s2 and in 10 s it passed 195 m. What is the speed of the uniform movement of the car and the speed at the end of the tenth second?

Option number 7 K-Mech.2

1. According to the equation of motion speed v= 5 + 2t, find the displacement of the body in a time equal to 5 s.

2. Write equations Sx(t) , ax(t) and vx(t). Build dependency graphs ax(t) and vx(t), if: v 0x = 20 m/s, a x = -2.5 m/s2.

3. What speed (average or instantaneous) are we talking about in the following cases: a) the speedometer on a diesel locomotive shows 75 km/h; b) a forest fire spreads at a speed of 25 km/h; c) the rocket reached a speed of 7 km/s.

4. The car, moving away, goes with acceleration a 1x = 3 m/s2. Having reached a speed of 54 km / h, it travels uniformly for a while, and then brakes with acceleration a 2x = -5 m/s2 to stop. Find the time of uniform motion of the car if it traveled a distance of 500 m to the stop.

Option No. 8 K-Mech.2

1. The bus is moving at a speed of 54 km/h. At what distance from the stop should the driver start braking if, for the convenience of passengers, the acceleration should not exceed 1.2 m/s2.

2. Construct graphs of the velocities of the bodies of the equation of motion, which have the form: v 1 = 12 - 3t and v 2 = 2t. After what time will the speeds of the bodies become the same?

3. Can a uniformly moving body have a positive projection of the acceleration vector?

4. A space rocket accelerates from rest and, having traveled a distance of 200 km, reaches a speed of 11 km/s. What is the rocket launch time? The motion of the rocket is assumed to be uniformly accelerated. Determine average speed missiles all the way.

Option number 9 K-Mech.2

1. For 0.1 s, the speed of the space rocket increased from 5 to 10 m/s. How fast was she moving?

https://pandia.ru/text/78/602/images/image006_6.jpg" align="left" width="144" height="107 src="> 1. Peregrine falcon, diving from a height on its prey , reaches a speed of 100 m / s. How far does it travel? The fall of the predator is considered free.

2. What information can be obtained from the velocity graphs of bodies? Write the velocity equations for the first and second bodies. Draw acceleration graphs for each of the bodies.

4. Body having initial speed v 0 = 2 m/s, moved uniformly for 3 seconds, then uniformly accelerated for 2 seconds with an acceleration of 2 m/s2, then for 5 seconds the acceleration was equal to 1 m/s2 and finally for 2 seconds uniformly with the speed obtained at the end of the last time interval. Find the final speed, the distance traveled and the average speed for the entire journey.

Option No. 12 K-Mech.2

1. When approaching the station, the train reduced the speed from 90 to 45 km/h within 25 seconds. Find the acceleration, assuming the motion is uniformly accelerated.

https://pandia.ru/text/78/602/images/image008_7.jpg" align="left" width="125" height="103 src="> 1. A freely falling body acquired a speed of 78 in 8 seconds, 4 m/s What is the initial velocity of this body?

2. According to the acceleration graphs of the bodies shown in the figure, plot the velocity graphs, considering: v 01x = 0; v 02x = 8 m/s.

3. The equation for the velocity of a moving body has the form v x = 5 + 4 t. What would be the corresponding displacement equation?

4. The train starts to move with uniform acceleration and in the first 10 seconds passes by the station attendant, who was at the beginning of the movement at the beginning of the first car. What speed will the train have after passing the tenth car on duty? The length of each wagon is 20 m, the gaps between the wagons are neglected.

Option No. 14 K-Mech.2

1. The trolleybus was moving at a speed of 14.4 km/h. The driver pressed the brake, the trolley bus stopped after 4 seconds. Determine the acceleration and stopping distance.

2. According to the equation of the speed of the body v x = 50 -10 t, plot graphs v x( t) and a x( t).

3. What speed (average or instantaneous) are we talking about: a) the turner processes the part with a cutting speed of 3500 m / min; b) the athlete at the finish had a speed of 10 m/s.

4. A car, having a speed of 32.4 km / h, increased it to 72 km / h in 22 seconds. Determine the movement of the car, assuming the movement is uniformly accelerated.

Option No. 15 K-Mech.2

1. Write the formula for the dependence of speed on time for the case when at the initial moment of time the speed of the body is 30 m/s and the acceleration is 2 m/s2. Calculate the speed of the body after 20 seconds from the start of the countdown.

2. According to the condition of the 1st task, construct graphs of the dependence of speed and acceleration on time.

3. What speed (average or instantaneous) are we talking about in the following cases: a) the speedometer on the plane shows 275 km/h;

b) the tractor sows the field at a speed of 20 km/h;

c) at the finish the athlete reached a speed of 2 m/s.

4. From what height did the body fall freely if 60 m flew over the last 2 s? How long has it been falling? Take g = 10 m/s2.

Option No. 16 K-Mech.2

1. With what acceleration did the rider move if his speed changed from 28.8 to 39.6 km / h in 15 seconds.

2. Construct a speed graph for movements for which: a) v 0x =10 m/s; a x = -2 m/s2; b) v 0x = 2 m/s; a x = 2 m/s2. How does speed depend on time in each case?

3. Which of the given dependencies describe uniformly accelerated motion? one) v x = 23 +2 t; 2) S x = 33 + 2t; 3) Sx = 43 t 2; 4) Sx = 65 t - t 2; 5) Sx = 22 - 3t + 4t2; 6) v x=4.

4. The speed of some body at time t1 = 3 s is equal to v 1x = 3 m/s, and at time t2 = 6 s the body's velocity is zero. Determine the path traveled by the body in 5 s from the start of time. A body moves in a straight line with constant acceleration.

Option No. 17 K-Mech.2

1. The car traveled a distance of 30 m, with what acceleration did it move if its speed at the initial moment of time was 14.4 km / h, and at the end of the path 10 m / s.

2. At what point in time is the speed of the body equal to zero, if it is given by the equation vx = t, build a graph vx(t) and find the speed module after 5 s, after the start of movement.

3. Two planes fly on a collision course, one with a decreasing modulus of speed from west to east, the other, accelerating from east to west. What is the direction of the acceleration of the aircraft?

4. A motorcyclist, starting off, goes with acceleration a 1 = 2 m/s2. Having reached a speed of 43.2 km / h, it travels evenly for a while, and then brakes with acceleration a 2 = 4 m/s2 to stop. Find the distance traveled by the motorcycle if the movement lasted 30 s.

Option No. 18 K-Mech.2

https://pandia.ru/text/78/602/images/image010_6.jpg" align="left" width="154" height="109"> 1. The car started moving in a straight line with a constant acceleration of 2 m/s2, at some point in time, its speed is 10 m / s. What movement did the car make during this time?

2. The equations of motion of bodies have the form: x 1 = 3; x 2 = 5 + 0,2t 2; x 3 = 2t - 3t 2; x 4 = 8 - 2t + 0,5t 2. Write the equations for the dependence of the speed of each of the bodies on time.

3. According to the speed graphs shown in the figure, determine the accelerations of the bodies. What is the nature of their movement?

4. A material point moves from a state of rest at the end of the second second, its speed is 10 cm/s. What speed will material point at the moment of passing the coordinate 100 cm. Take the initial coordinate of the point x 0 = -10 cm.

Option No. 20 K-Mech.2

DIV_ADBLOCK31">

3. Two pebbles are released from the hands, from the same height, one after the other after 1 s. According to what law will the distance between them change with their further fall?

4. The car, moving uniformly, switched to uniformly accelerated motion with an acceleration of 2 m/s2, traveled a distance of 250 m in 10 s. What is the final speed?

Option No. 21 K-Mech.2

https://pandia.ru/text/78/602/images/image013_3.jpg" align="left" width="129" height="190">1. How long does it take for the harvester to move from rest with an acceleration of 1 m / s2 to acquire a speed of 25.2 km / h.

2. According to the graphs shown in the figure, determine the acceleration of bodies and write expressions for the dependence of the speed and displacement of these bodies on time.

3. How will the density of rain (the number of drops in 1 m3) change as it approaches the Earth's surface?

4. A train moving after the start of deceleration with an acceleration of 0.4 m/s2 stopped after 25 s. Find the stopping distance.

Option No. 23 K-Mech.2

1. The sleigh descends the mountain 8 s. The initial speed of the sleigh is 2 m/s, the acceleration is 40 cm/s2. Determine the speed of the sleigh at the foot of the mountain.

2. Construct graphs of speed and acceleration versus time for two bodies: a) v 01 = 45 m/s; a 1 = -5 m/s2; b) v 02 = 10 m/s; a 2= 2 m/s2.

3. Why can't we talk about the average speed of variable motion in general, but can we only talk about the average speed for a given period of time or about the average speed on a given section of the path?

4. Two bodies simultaneously started moving in one direction from one point: one - uniformly with a speed of 16 m / s, and the other - uniformly accelerated, acquired a speed of 4 m / s in the first second of its movement. How long will it take for the second body to overtake the first?

Option No. 24 K-Mech.2

1. The body moves uniformly with acceleration Oh=-2 m/s2. At what distance from the starting point will the body be 5 s after the start of the time reference if the initial speed is 10 m/s?

vx=-3 + 6t, build a graph of the speed and find its modulus 5 s after the start of the countdown. At what point in time was the body's velocity zero?

3. Is it possible to determine the average speed for the entire driving time from the data for several minutes, taken every minute while driving a car?

4. The balloon descends at a constant speed of 5 m/s. At a distance of 50 m from the ground, a small and heavy object fell out of it. How much later will the balloon land than this object? Ignore air resistance for a falling object.

Option No. 25 K-Mech.2

1. A ball moves uniformly along the floor, with an initial speed of 0.64 m/s and an acceleration of 16 cm/s2. How far will it go before stopping?

2. Plot graphs of speed and acceleration versus time if: v 0x = 500 m/s; ax= -50 m/s2.

3. Two bodies are thrown down: one without initial speed, the second - with the initial speed. What can be said about the accelerations of these bodies? Air resistance is ignored.

4. The body moves uniformly accelerated and travels 12 m in the sixth second. Determine the acceleration and speed after ten seconds of movement if the initial speed was zero.

Option No. 26 K-Mech.2

1. The snowmobile traveled 40 m in 8 s, with an acceleration of 1 m/s2. What is the initial speed?

2. According to the graph, give a description of the movement for bodies ( a) and ( b) shown in the figure. Write the equations of velocity versus time for each body, assuming that the initial speed of the bodies is zero.

3. At the point in time t\u003d 6 s, the speed of the aircraft is 230 km / h, what speed are we talking about?

4. The car was moving along a straight section of the road at a constant speed of 72 km/h. At a distance of 48.5 m from the traffic light, the driver applied the brakes. 4 s after that, the speed became 4 m/s. Find the position of the car relative to the traffic light.

Option No. 27 K-Mech.2

1. According to the equation of the speed of the body v x = 15 + 8 t, find its displacement in 10 s.

2. Plot graphs of speed and acceleration versus time if v 0 = 400 m/s, a= -25 m/s2.

3. What speed (average or instantaneous) are we talking about in the following cases: a) a company of soldiers is moving at a speed of 5 km/h;

b) the speedometer of the car shows 75 km/h;

c) when taking off from the machine gun, the speed of the bullet is 500 m / s.

4. The train was moving at a speed of 72 km/h. Find the braking time if the braking distance is 800 m?

Option No. 28 K-Mech.2

1. How far did the bus travel if its initial speed was 7.2 km/h and its final speed was 10 m/s, and it moved with an acceleration of 1 m/s2.

2. According to the graph shown in the figure, determine the accelerations of bodies, write expressions for the speed and movement of these bodies.

3. What speed are we talking about: at the time of hitting the target, the arrow had a speed of 3 m / s.

4. The snowmobile traveled 40 m in 8 s, with an acceleration of 1 m/s2. What is the speed gained by the sleigh?

Option No. 29 K-Mech.2

1. A body falls freely without initial velocity. What top speed it can have if the drop height is 10m?

2. Construct speed graphs for the movement of two bodies, in which: a) v 01 = 2 m/s; a 1=0; b) v 02 = 0; a 2 = 2 m/s2. How does speed depend on time in each case?

3. In what case is the distance traveled in the first second in uniform motion numerically not equal to half the acceleration?

4. The dump truck, moving downhill, traveled 340 m in 20 s and developed a speed of 24 m/s. Assuming the movement is uniformly accelerated, find the acceleration of the dump truck and its speed at the beginning of the slope.

Option No. 30 K-Mech.2

1. A bus with a speed of 5 m/s began to move with a constant modulo acceleration of 0.5 m/s2, directed in the same direction as the velocity vector. Determine the speed of the car after 15 seconds.

2. The speed is given by the equation v x = 16 + 2 t, build graphs of speed and acceleration versus time. Write the dependence equation x( t), consider x0=40 m.

3. The figure shows the acceleration vector. What is the nature of the movement if the body moves to the left? to the right?

4. An arrow flying at a speed of 50 m/s hits a wooden board. Find the penetration depth of the arrow if it moved in the tree for 0.005 s. The motion in the tree is assumed to be uniformly accelerated. With what acceleration did the arrow move in the tree?

Answers of control work No. 2: "Rectilinear uniformly accelerated motion"


v x= v o + at= 20 m/s	a x = 2 m/s2	Equivalents Ravnousk.	600000 m/s2; 0.3 m; v cf=300 m/s
a= 1 m/s2	a x( t) = 1 v x( t) = 5 - t vx(10)=-5 m/s	Instant
	0 m/s; 13.5 m; 9 m/s; x 2=27 m; 0 m/s; 13.5 m	instant
a x( t) =3 v x(t) = 5+3 . t S x( t)=5. t+1.5 . t2			v k \u003d 30 m / s v cf=15 m/s
	v 2x=5+2 . t;
	v x( t)=12-8. t a x( t)=-8; 1.5 s	Equal Ukrainian Equivalents	v 1=12 m/s v 2=27 m/s
	Sx=20 . t-1.25t2; a x(t)=-2.5 v x( t)=20-2,5. t	a) instants. b) cf. sk. c) inst. sk.
		Yes, if v x<0	v cf=5.55 km/s
a=50 m/s2		rests; equal.; equiv.	v avg.=32 km/h

	v 1=5+3. t; v 2=15-3. t	cf. sk. different	v con=11m/s; 78.5m; v cf=6.54 m/s
	v 1=2. t; v 2=10-2,5. t	slow down accel.
	v x1=15 . t; v x2=8-10t	s=5 . t+2t2
		a) cf.; b) instant.
v =30+2. t; v(20)=70		a) instant; b) cf; c) instant
	v 1=10-2. t; v 2=2+2. t
		from east to west
	v 1 =15 m/s; v 2 = -10 m/s	about average
	v 1=0; v 2=0,4t v3= 2-6t; v4=-2+t	6 m/s2 - set; -2 m/s2-deputy
	v 1=2+3. t; v 2=6-3. t	s=10 . t+5

	v x1=3 . t; v x2=8-2t; sx1=1.5 . t2; 3 m/s2; -2 m/s2; sc2=8 . t-t2;
	v 1=45-5. t; v 2=10+2. t	Wed sk. different

	vx=500-50. t;	are the same	2.18 m/s2; 21.82 m/s
	ax=-1,5 v x1=2 . t; v x2=-1.5 t	inst. speed
	v x=400-25 t
	v x1 = 6 -2 . t; sx1=6 . t-t2; v x2=2+2 . t; sx2=2 . t+t2	instantaneous speed
	v 1 =2 m/s; v 2 = 2. t		v 0 =10 m/s
	x 1= 40+16t+t2	equiv. (left); equivalent (right)

option 1

The train approaches the station at a speed of 21.6 km/h and stops a minute after the start of braking. How fast was the train moving?

During emergency braking, a car moving at a speed of 72 km/h stopped after 5 s. Find the stopping distance.

Rectilinear uniformly accelerated motion option 2

A car moving at a speed of 30 m/s starts to slow down. What will be its speed after 1 minute if the acceleration during deceleration is 0.3 m/s2?

The bus, moving away from the stop, moves with an acceleration of 0.2 m/s2. At what distance from the start of the movement will its speed become equal to 10 m/s?