Advertisements
Advertisements
प्रश्न
A ball of mass 200 g falls from a height of 5 metres. What is its kinetic energy when it just reaches the ground? (g = 9.8 m/s2)
Advertisements
उत्तर
Mass of the ball, (m) = 0.2 kg
Height from which the ball is dropped, (h) = 5 m
Initial velocity of the ball, (u) = 0 m/s
Acceleration due to gravity, (g) = 9.8 m/s2
Let the final velocity of the ball when it just reaches the ground be (v)
We will use the third equation of motion to find the velocity of the ball when it just reaches the ground,
v2 = u2 + 2as
So,
v2 = 0 + 2(9.8)(5)
⇒ v2 = 98
Now we can find the kinetic energy as,
`K.E = 1/2 mv^2`
Therefore,
K.E = (1/2)(0.2)(98)
⇒ K.E = 9.8 J
So, the kinetic energy of the moving object is 9.8 J.
APPEARS IN
संबंधित प्रश्न
Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?
A cannon ball of mass 500 g is fired with a speed of 15 m s-1. Find:
- its kinetic energy.
- its momentum.
A body is thrown vertically upwards. Its velocity keeps on decreasing. What happens to its kinetic energy as its velocity becomes zero?
By how much will the kinetic energy of a body increase if its speed is doubled?
If the speed of a body is halved, what will be the change in its kinetic energy?
On what factors does the kinetic energy of a body depend?
What do you understand by the kinetic energy of a body?
A car is accelerated on a levelled road and attains a speed of 4 times its initial speed. In this process, the kinetic energy of the car :
If an object has 0 momentum, does it have kinetic energy? Explain your answer.
Water stored in water dams possesses kinetic energy.
