Force Test - 2...

A large truck and a car moving with same velocity have a head on collision. Which of the following is an INCORRECT statement?

A particle of mass m is tied to a light string and rotated with a speed v along the circular path of the radius 'r' in horizontal plane. If T is the tension in the string and mg = gravitational force on the particle, then pick the correct option(s).

i. mg will act radially outward
ii. mg will act vertically downward
iii. Tension will act radially outward
iv. Tension will act radially inward

Which of the following assumptions is/are made in the law of conservation of momentum?

(i) Initial velocity of the object is zero.
(ii) Initial and final velocities of the object remain constant.
(iii) There is no external unbalanced force that acts on the system.