Question

10. An object of mass 2 kg is thrown vertically upwards with an initial velocity of 20m/s. What will be
its Potential energy at the end of 3 seconds ? (Assume g=10m/s2). (3)​

Answer 1

Answer :

• Potential energy = 2100 J

S O L U T I O N :

Given,

• Mass (m) = 2 kg
• Initial velocity (u) = 20 m/s
• Time (t) = 3 s
• Acceleration due to gravity (g) = 10 m/s²

To Find,

• The Potential energy of the object at the end of 3 seconds.

Explanation,

Applying 2nd equation of motion,

S = ut + 1/2 × at²

[ °.° s = h & a = g ]

=> h = ut + 1/2 × gt²

[ Put the values ]

=> h = 20 × 3 + 1/2 × 10 × (3)²

=> h = 60 + 5 × 9

=> h = 60 + 45

=> h = 105 m

Applying potential energy formula,

P.E = mgh

[ Put the values ]

=> U = 2 × 10 × 105

=> U = 20 × 105

=> U = 2100 J

Therefore,

The Potential energy of the object at the end of 3 seconds is 2100 J.