Question

P2 = Mv + m (v
(200 kg) v + (20 kg) (u - 4 ms)
GUIDELINES FOR NCERT PROBLEM
C
acceler
to the
1. Give the magnitude and direction of the 'net
g = 9.8
force acting on :
(a) a raindrop falling down with constant speed,
(b) a cork of mass 10 g floating on water,
(c) a kite maintained stationary in the sky,
A
(d) a car moving with a constant velocity of
30 km/h on a rough road,
F=md
(e) a high-speed electron in space far from all F= 0.1
gravitating objects and free of electric and magnetic (
fields.
​

Answer 1

Answer:

(a) As the raindrop is falling with a constant speed, its acceleration, a=0. Hence net force F=ma=0.

(b) As the cork is floating on water, its weight is balanced by the upthrust due to water. Therefore, the net force on the cork is 0.

(c) As the kite is held stationary, in accordance with the first law of motion, the net force on the kite is 0.

(d) Force is being applied to overcome the force of friction. But as the velocity of the car is constant, its acceleration, a=0. Hence net force on the car F=ma=0.

(e) As the high-speed electron in space is far away from all gravitating objects and free of electric and magnetic fields, the net force on the electron is 0.