Exam

JIPMER

Year

2009

Subject

Physics

Chapter

Work, Power and Energy

JIPMER 2009 · Physics · Work, Power and Energy

A particle of mass 100 g is thrown vertically upwards with a speed...

A particle of mass 100 g is thrown vertically upwards with a speed of $5 \mathrm{~m} / \mathrm{s}$. The work done by the force of gravity during the time the particle goes up is

Step-by-step solution

The height ( $h$ )traversed by particle while going up is $h=\frac{u^2}{2 g}=\frac{25}{2 \times 9.8}$ Work done by gravity force $=m \overrightarrow{\mathbf{g}} \cdot \overrightarrow{\mathbf{h}}$ $=0.1 \times g \times \frac{25}{2 \times 9.8} \cos 180^{\circ}$ [Angle between force and displacement is $180^{\circ}$ ] $\therefore W=-0.1 \times \frac{25}{2}=-1.25 \mathrm{~J}$