Chap#03 Force and Motion Flashcards
To get a resultant displacement of 10m, two displacement vectors of magnitude 6m and 8m should be combined
Perpendicular to each other
The velocity of a particle at an instant is 10 m/s and after 5s the velocity of the particle is 20 m/s. The velocity 3s before in m/s is:
4
A motorist travels from A to B at a speed of 40 km/h and returns at a speed of 60 km/h. His average speed will be:
48 km/h
The sum of the magnitude of two forces acting at a point is 18 and the magnitude of their resultant is 12. If the resultant is at 90° with the force of the smaller magnitude, then their magnitudes are:
5, 13
A train of 150m in length is going in the north direction at a speed of 10 m/s. A parrot flies at a speed of 5 m/s towards the south direction parallel to the railway track. The time taken by the parrot to cross the train is equal to:
10 s
What will be the ratio of the distance moved by a freely falling body from rest in 4th and 5th seconds of journey?
7 : 9
A boy is dropped from a tower with zero velocity, reaches ground in 4s. The height of the tower is about:
80 m
The acceleration ‘a’ in m/s^2 of a particle is given by a= 3t^2 +2t +2, where ‘t’ is the time. If the particle starts out with a velocity v = 2 m/s at t=0, then the velocity at the end of 2 second is:
24 m/s
The initial velocity of a body moving along a straight line in 7 m/s. It has a uniform acceleration of 4 m/s^2. The distance covered by the body in the 5th second of its motion is:
25 m
Which of the following four statements is false?
➡A body can have zero velocity and still be accelerated❌
➡A body can have a constant velocity and still have a varying speed✅
➡A body can have a constant speed and still have varying velocity❌
➡The direction of the velocity of a body can change when its acceleration is constant❌
