Motion in a Straight Line Questions and Answers Part-1

1. A Body moves 6 m north. 8 m east and 10m vertically upwards, what is its resultant displacement from initial position
a) \[10\sqrt{2m}\]
b) 10 m
c) \[\frac{10}{\sqrt{2}}m\]
d) \[10\times 2m\]

Answer: a

2. A man goes 10m towards North, then 20m towards east then displacement is
a) 22.5m
b) 25m
c) 25.5m
d) 30m

Answer: a

3. A person moves 30 m north and then 20 m towards east and finally \[30\sqrt{2 }m\]  in south-west direction. The displacement of the person from the origin will be
a) 10 m along north
b) 10 m long south
c) 10 m along west
d) Zero

Answer: c

4. An aeroplane flies 400 m north and 300 m south and then flies 1200 m upwards then net displacement is
a) 1200 m
b) 1300 m
c) 1400 m
d) 1500 m

Answer: a

5. An athlete completes one round of a circular track of radius R in 40 sec. What will be his displacement at the end of 2 min. 20 sec
a) Zero
b) 2R
c) \[2\pi R\]
d) \[7\pi R\]

Answer: b
Explanation: Total time of motion is 2 min 20 sec = 140 sec. As time period of circular motion is 40 sec so in 140 sec. athlete will complete 3.5 revolution i.e., He will be at diametrically opposite point i.e., Displacement = 2R.

6. A wheel of radius 1 meter rolls forward half a revolution on a horizontal ground. The magnitude of the displacement of the point of the wheel initially in contact with the ground is
a) \[2\pi \]
b) \[\sqrt{2\pi} \]
c) \[\sqrt{\pi^{2}+4} \]
d) \[\pi\]

Answer: c

7. A person travels along a straight road for half the distance with velocity \[v_{1}\] and the remaining half distance with velocity \[v_{2}\] The average velocity is given by
a) \[v_{1}v_{2}\]
b) \[\frac{V_2^2}{V_1^2}\]
c) \[\frac{v_{1}+v_{2}}{2}\]
d) \[\frac{2v_{1}v_{2}}{v_{1}+v_{2}}\]

Answer: d

8. The displacement-time graph for two particles A and B are straight lines inclined at angles of \[30^{\circ}\] and \[60^{\circ}\] with the time axis. The ratio of velocities of \[{v_{A}:v_{B}}\]  is
a) \[1:2\]
b) \[1:\sqrt{3}\]
c) \[\sqrt{3}:1\]
d) \[1:3\]

Answer: d

9. A car travels from A to B at a speed of 20 km / hr and returns at a speed of 30 km / hr . The average speed of the car for the whole journey is
a) \[25 km\diagup hr\]
b) \[24 km\diagup hr\]
c) \[50 km\diagup hr\]
d) \[5 km\diagup hr\]

Answer: b

10. A boy walks to his school at a distance of 6 km with constant speed of 2.5 km/hour and walks back with a constant speed of 4 km/hr. His average speed for round trip expressed in km/hour, is
a) 24/13
b) 40/13
c) 3
d) 1/2

Answer: b