A block of mass 5 kg starting from rest pulled up on a smooth incline plane making an angle of 30 ° with horizontal with an effective acceleration of 1 m s - 2 . The power delivered by the puling forc

Question

A block of mass 5 kg starting from rest pulled up on a smooth incline plane making an angle of 30 ° with horizontal with an effective acceleration of 1 m s - 2 . The power delivered by the puling force at t = 10 s from the start is _____ W . [Use g = 10 m s - 2 ] (Calculate the nearest integer value)

TestHub · Accepted Answer

Let's consider the following free-body diagram:

From the above diagram, it can be written that

$F - m g \sin 30 ° = m a . . . (1)$

Substitute the values of the known parameters into equation (1) and solve to calculate the force applied on the block.

$\begin{array}{rcl} F - 50 \sin 30 ° & = & 5 \times 1 \\ \Rightarrow & F = (5 + 25) N \\ = & 30 N \end{array}$

The velocity of the block $(v)$ at $t = 10 s$ can be written as

$\begin{array}{rcl} v & = & 0 + 1 m s^{- 2} \times 10 s \\ = & 10 m s^{- 1} \end{array}$

Hence, the required power is given by

$\begin{array}{rcl} P & = & F v \\ = & 30 N \times 10 m s^{- 1} \\ = & 300 W \end{array}$

Physics - W.E.P. Question with Solution | TestHub

Doubts & Discussion