Velocity and Time
Subjective
Srivastava’s
Srivastava’s
MOTION IN ONE DIMENSION
1.
A particle is projected vertically upwards with a velocity 20 m s1 from the top of the tower of height 100 m. Determine the time it takes to reach the ground.
Answer: t 2 1 6 sec.
A particle is dropped from the top of the tower of height h. At the same instant another particle is projected vertically upwards from the bottom of the tower with such a velocity that it will be able to just reach the top of the tower. When and at what height from ground the two particles meet?
3h
h
Answer: t and x
2g
4
2.
3.
4.
5.
A car covers first half of the total journey with uniform velocity 40 m s1 and the other half of the journey with uniform velocity 60 m s1. Find its average velocity in the entire journey.
Answer: 48 m s1
A cyclist moves from A to B with uniform speed v0. While returning from B to A it travels for half the time with uniform speed v1 and for the other half the time with uniform speed v2. Find the average speed of the cyclist for the complete journey.
2v 0 v 1 v 2
Answer: v
2v 0 v 1 v 2
Front end of a uniformly accelerated train crosses a telegraph post with velocity u.
Its rear end crosses the same post with velocity v. Find the velocity with which mid point of the train crosses the same post.
u2 v2
2
6. The engine of a boat moving with velocity v0 is switched off. Due to resistance of water it experiences a deceleration whose magnitude is directly proportional to instantaneous velocity given by a kv , where k is a constant. Find the distance it covers before it stops. v Answer: s 0 k 7. Two stones are projected vertically up wards one after the other with same velocities
20 m s1 with a time interval of 2 sec. After what time and at what height from point of projection do they meet?
Answer: t 1 and s 15 m. th 8. A particle dropped from the top of a tower, covers 9 of the total height in its
25
last second of journey. Find the height of the tower.
Srivastava’s
Srivastava’s
MOTION IN ONE DIMENSION
1.
A particle is projected vertically upwards with a velocity 20 m s1 from the top of the tower of height 100 m. Determine the time it takes to reach the ground.
Answer: t 2 1 6 sec.
A particle is dropped from the top of the tower of height h. At the same instant another particle is projected vertically upwards from the bottom of the tower with such a velocity that it will be able to just reach the top of the tower. When and at what height from ground the two particles meet?
3h
h
Answer: t and x
2g
4
2.
3.
4.
5.
A car covers first half of the total journey with uniform velocity 40 m s1 and the other half of the journey with uniform velocity 60 m s1. Find its average velocity in the entire journey.
Answer: 48 m s1
A cyclist moves from A to B with uniform speed v0. While returning from B to A it travels for half the time with uniform speed v1 and for the other half the time with uniform speed v2. Find the average speed of the cyclist for the complete journey.
2v 0 v 1 v 2
Answer: v
2v 0 v 1 v 2
Front end of a uniformly accelerated train crosses a telegraph post with velocity u.
Its rear end crosses the same post with velocity v. Find the velocity with which mid point of the train crosses the same post.
u2 v2
2
6. The engine of a boat moving with velocity v0 is switched off. Due to resistance of water it experiences a deceleration whose magnitude is directly proportional to instantaneous velocity given by a kv , where k is a constant. Find the distance it covers before it stops. v Answer: s 0 k 7. Two stones are projected vertically up wards one after the other with same velocities
20 m s1 with a time interval of 2 sec. After what time and at what height from point of projection do they meet?
Answer: t 1 and s 15 m. th 8. A particle dropped from the top of a tower, covers 9 of the total height in its
25
last second of journey. Find the height of the tower.