Question

a ball of mass 25g moving with a velocity of 2m/s is stopped with in 5cm.The average resistance offered to the ball
a) 10N
b) 5N
c) 2N
d) 1N​

Answer 1

Given :

Mass (m) = 25 g = 25 × $10^{-3}$ Kg

Velocity (v) = 2 m/sec

Distance the ball travelled after coming to rest = 5 cm = 5×$10^{-2}$ m

To Find :

The average resistance offered to the ball

Solution :

When the ball came to rest, its kinetic energy get converted into potential energy. So,

        Kinetic Energy of the ball = Potential Energy of the ball

or,          $\frac{1}{2} mv^{2}$                             = Force × Displacement

or,          $\frac{1}{2}$×25×$10^{-3}$×(2)²             = Force × 5 ×$10^{-2}$

or,          50×$10^{-3}$                        = Force × 5 ×$10^{-2}$

or,          Force                            = $\frac{50 * 10^{-3} }{5*10^{-2} }$

∴            Force                            = 1 N

∴The average resistance offered to the ball is 1 N.

The correct option is (d) 1 N