A particle of mass is projected along a straight line with an initial speed of

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A particle of mass

1.5\,\text{kg}

is projected along a straight line with an initial speed of

4\,\text{m\,s}^{-1}

. A constant acceleration of

2\,\text{m\,s}^{-2}

acts on it in the direction of motion. Answer the following. (i) Write the expression for its speed

v(t)

at any time

t

seconds after projection. (ii) Obtain the expression for the instantaneous power supplied by the net force at time

t

, and hence calculate the power at

t=3\,\text{s}

. (iii) Determine the time at which the instantaneous power first reaches

100\,\text W