Question

The linear momentum p of a body moving in one dimension varies with time according to the equation $p = a + bt^{2}$, where a and b are positive constants. The net force acting on the body is

• A. Proportional to $t^{2}$
• B. A constant
• C. Proportional to t
• D. Inversely proportional to t

Answer 1

Answer: (C)

Proportional to t

Answer 2

$\overrightarrow{F} = \frac{d\overrightarrow{p}}{dt}$= $\frac{d}{dt}(a + bt^{2}) = 2bt$ i.e. $F \propto t$