A tennis ball of mass 350 g is thrown vertically upwards at a speed of 4 m/s. If M is the maximum gravitational potential energy of the ball and H is the maximum height it reaches, then which one of the following is correct? (Take \(g = 10 \, m/s^2\))
M = 2.8 J, H = 0.8 m
Given mass \(m = 350 \, g = 0.35 \, kg\) and initial upward speed \(u = 4 \, m/s\). The maximum height reached is \(H = \frac{u^2}{2g} = \frac{4^2}{2 \times 10} = \frac{16}{20} = 0.8 \, m\). By conservation of energy, the maximum gravitational potential energy equals the initial kinetic energy: \(M = \frac{1}{2}mu^2 = \frac{1}{2} \times 0.35 \times 16 = 2.8 \, J\). Hence \(M = 2.8 \, J\) and \(H = 0.8 \, m\).
Important Questions from Conservation of Mechanical Energy
Which of the following equation is also a special case of the work-energy (WE) theorem? (where a is acceleration, u and v are the initial and final speeds and s the distance traversed.)
A uniform chain of mass m and length l is placed on a smooth horizontal table such that \(\frac{1}{4}\)th of its length is hanging from the edge of the table. The chain slips down. Find the kinetic energy of the chain when half of its length is hanging from the edge of the table.
When a particle is projected upwards, its kinetic energy
Work done on body equals to change in its kinetic energy is known as
The Instrument converting mechanical energy into electrical energy is called
