Given: - Mass of the ball: \( m = 120 \, \text{g} = 0.12 \, \text{kg} \) - Initial speed of the ball: \( v = 25 \, \text{m/s} \) - Time taken to catch the ball: \( t = 0.1 \, \text{s} \) - Final speed of the ball: \( v_f = 0 \, \text{m/s} \) (since the ball is caught and comes to rest)
The change in momentum (\( \Delta p \)) of the ball is given by:
\[ \Delta p = m \cdot (v_f - v) \]
Substituting the given values:
\[ \Delta p = 0.12 \cdot (0 - 25) \, \text{kg} \cdot \text{m/s} \] \[ \Delta p = -3 \, \text{kg} \cdot \text{m/s} \]
The negative sign indicates a decrease in momentum.
The force exerted by the ball on the hand of the player is given by Newton’s second law:
\[ F = \frac{\Delta p}{t} \]
Substituting the values:
\[ F = \frac{-3}{0.1} \, \text{N} \] \[ F = -30 \, \text{N} \]
The magnitude of the force is:
\[ |F| = 30 \, \text{N} \]
The magnitude of the force exerted by the ball on the hand of the player is \( 30 \, \text{N} \).
A horizontal force is exerted on a 20 kg box to slide it up on an inclined plane with an angle of 30°. The frictional force retarding the motion is 80 N. If the box moves with a constant speed, then the magnitude of the force is:(Take g=10 ms-2)
A body of mass 1000 kg is moving horizontally with a velocity of 6 m/s. If 200 kg extra mass is added, the final velocity (in m/s) is: