Three different objects of mass and m3 are allowed to fall from rest and from the same point ‘O’ along three different frictionless paths. The speeds of the three objects, on reaching the ground, will be in the ratio of:
1.
2.
3. 1 : 1 : 1
4.
When a body moves with a constant speed along a circle
(1) No work is done on it
(2) No acceleration is produced in the body
(3) No force acts on the body
(4) Its velocity remains constant
A sphere of mass m is tied to end of a string of length l and rotated through the other end along a horizontal circular path with speed v. The work done by centripetal force in full horizontal circle is
(1) 0
(2)
(3)
(4)
In a circus stuntman rides a motorbike in a circular track of radius R in the vertical plane. The minimum speed at highest point of track will be
(1)
(2) 2gR
(3)
(4)
A ball is suspended by a thread of length l. What minimum horizontal velocity has to be imparted to the ball for it to reach the height of the suspension:
(1) gl
(2) 2 gl
(3)
(4)
As per the given figure to complete the circular loop, what should be the radius of the loop?
1. 4 m
2. 3 m
3. 2.5 m
4. 2 m
A stone of mass 1 kg tied to a light inextensible string of length is whirling in a circular path of radius L in a vertical plane. If the ratio of the maximum tension in the string to the minimum tension in the string is 4 and if g is taken to be 10 m/sec2, the speed of the stone at the highest point of the circle is
(1) 20 m/sec
(2)
(3)
(4) 10 m/sec
A small block is shot into each of the four tracks as shown below. Each of the tracks rises to the same height. The speed with which the block enters the track is the same in all cases. At the highest point of the track, the normal reaction is maximum in:
(1) | |
(2) | |
(3) | |
(4) | Same in all cases |
A stone tied to a string of length L is whirled in a vertical circle with the other end of the string at the centre. At a certain instant of time, the stone is at its lowest position and has a speed u. The magnitude of the change in its velocity as it reaches a position where the string is horizontal is:
(1)
(2)
(3)
(4)
The driver of a car travelling at velocity v suddenly sees a broad wall in front of him at a distance d. He should
(1) Brake sharply
(2) Turn sharply
(3) (1) and (2) both
(4) None of the above