Maximum power of gravitational force on projected body – Rankers Physics

Power: Practice Problem & Solution

A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest (2011 Pre)
At the highest position of the body
At the instant just before the body hits the earth
It remains constant all through
At the instant just after the body is projected

Solution Explained:

To solve this problem, we apply the core principles of Power. Understanding the underlying formula is key to arriving at the correct answer below:

Power is $P = \vec{F} \cdot \vec{v} = Fv$. The gravitational force is downward and speed is maximum at the instant just before the body hits the earth, making the power exerted by gravity greatest at that moment.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. A vertical spring with force constant \(k\) is fixed on a table. A ball of mass \(m\) at a height \(h\) above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance \(d\). The net work done in the process is: (2007)
2. The kinetic energy acquired by a mass \(m\) in travelling distance \(d\), starting from rest, under the action of a constant force is directly proportional to: (1994)
3. Assertion (A): A spring has potential energy, both when it is compressed or elongated. Reason (R): In compressing or stretching, work is done on the spring against the restoring force.  
4. A body of mass 10 kg moves along a smooth inclined plane \( \theta = 30^\circ\) with constant velocity through a distance of 10 m. Calculate the work done by applied external force to move the body through desired distance of 10 m.
5. Assertion (A): Work done by conservative force along closed path is zero. Reason (R): When an object is moved along closed path beginning and ending are at same point its displacement is zero.