MOTION IN A STRAIGHT LINE

1. A particle is dropped from rest an another 6. The distance between two particles is
particle is thrown downward decreasing at the rate of 6 m/s. When they
simultaneously with initial speed u, then are moving in the opposite direction. If
(a) Time after which their separation these particles travel with the same initial
becomes h, is speeds and in the same direction, then the
separation increases at the rate of 4 m/s.
(b) Their relative velocity is always
(c) Their relative acceleration is always zero The particles have speed as :
(a) 5 m/s, 1 m/s (b) 4 m/s, 1 m/s
(d) All of these
(c) 4 m/s, 2 m/s (d) 5 m/s, 2 m/s
2. A student is standing at a distance of 50
7. A stone is dropped from a height h
meters from the bus. As soon as the bus
begins its motion with an acceleration of 1 simultaneously; another stone is thrown up
from the ground which reaches a height 4 h.
, the student starts running towards
The two stones cross each other after time.
the bus with a uniform velocity u. Assuming
the motion to be along a straight road, the (a) √ (b) √
minimum value of , so that the student is
able to catch the bus is – (c) √ (d) √
(a) (b)
(c) (d)
8. Two cars are moving in the same direction
with the same speed 30m/h. They are
3. A man is 45 m behind the bus when the bus
separated by a distance of 5 km, the speed
starts acceleration from rest with
of a car moving in the opposite direction if
acceleration of 2.5 . With what
it meets these two cars at an interval of 4
minimum velocity should the man start
minutes, will be-
running to catch the bus?
(a) 40 km/hr (b) 45 km/hr
(a) (b)
(c) 30 km/hr (d) 15 km/hr
(c) (d)
9. Two cars are travelling towards each other
4. Two trains, each 50 m long are travelling in
at speed of 20 each. When the cars
the opposite direction with velocity 10 m/s
are 300 m apart, both the drivers apply
and 15 m/s. The time of crossing is:
brakes and the cars retard at the rate of
(a) 10 sec (b) 4 sec
. The distance them when they
(c) 2√ sec (d) 4√ sec come to rest is:
(a) 25 m (b) 100 m
5. A train of 150 meter length is going towards (c) 50 m (d) 200 m
north direction at a speed of 10 m/sec
towards south direction parallel to the 10. A girl reached the metro station and found
railway track. The time taken by the parrot that the escalator was not working. She
to cross the train is- walked up the stationary escalator in time,
(a) 12 sec (b) 8 sec . On another day, if she remains
(c) 15 sec (d) 10 sec stationary on the moving escalator, then
 MOTION IN A STRAIGHT LINE

the escalator takes her up in time . The 15. The speed of swimmer is in still
time taken by her to walk up on the moving water. If the swimmer makes his strokes
escalator will be. normal to the flow of river of width 1 km,
(a) (b) he reaches a point 750 m down the stream
(c) (d) on the opposite bank. The speed of the
river water is ………….. .
11. The speed of a boat in still water is half of (a) 3 (b) 4
the velocity of the flow of water (v). At what (c) 5 (d) 6
angle boat should steer with the direction
of flow of water so that drift of boat is 16. A butterfly is flying with a velocity √
minimum? in North-East direction. Wind is slowly
(a) 30° (b) 60° blowing at from north to south. The
(c) 90° (d) 120° resultant displacement of the butterfly in 3
seconds is:
12. A man can row boat with 8 km/h in still (a) 12√ m (b) 20 m
water. He is crossing a river of width 8 km, (c) 3 m (d) 15 m
where the speed of water flow is 4 km/h.
What direction should he head the boat to 17. The stream of a river is flowing with a speed
cross the river in the shortest time? of 2 . A swimmer can swim at a speed
(a) 30° with the current of . What should be the direction of
(b) 60° with the current the swimmer with respect to the flow of the
(c) 90° with the current river to cross the river straight?
(d) 120° with the current (a) 90° (b) 120°
(c) 150° (d) 60°
13. When a man walks on a horizontal road
with velocity 1 km/h, the rain appears to 18. A man standing on a road has to hold his
him coming vertically at a speed of 2 km/h. umbrella at 30° with the vertical to keep the
The actual speed of the rain w.r.t. ground is: rain away. He throws the umbrella and
starts running at 10 . He finds that
(a) √ km/h (b) √ km/h
raindrops are hitting his head vertically.
(c) 1 km/h (d) 3 km/h
What is the speed of rain with respect to
ground?
14. A ship A is moving Westwards with a speed
of 10 and a ship B 100 km south of (a) √ (b) 20
A, is moving northwards with a speed of 10 (c) (d)
√ √
. The time after which the distance
between them becomes shortest, is 19. A stationary man observes that the rain is
(a) 5√ h (b) 10√ h falling vertically downward. When he starts
(c) 0 h (d) 5 h running with a velocity of he
observes that the rain is falling at an angle
60° with the vertical. The actual velocity of
rain is
 MOTION IN A STRAIGHT LINE

(a) √ (b) √
(c) √ (d) √

20. A car with a vertical wind shield moves

along in a rain storm at speed of 40 km/hr.
The rain drops fall vertically with a terminal
speed of 20 m/sec. The angle at which the
rain drops strike the wind shield is
(a) ( ) (b) ( )
(c) ( ) (d) ( )

1. Ans = d
2. Ans = c
3. Ans = c
4. Ans = b
5. Ans = d
6. Ans = a
7. Ans = a
8. Ans = b
9. Ans = b
10. Ans = b
11. Ans = d
12. Ans = c
13. Ans = b
14. Ans = d
15. Ans = a
16. Ans = d
17. Ans = b
18. Ans = b
19. Ans = c
20. Ans = a