A block of mass 5kg starting from rest pulled up on a smooth...

Let's consider the following free-body diagram:

From the above diagram, it can be written that

$F - mgsin30 ° = ma . . . \left(1\right)</p><p>Substitute$ the values of the known parameters into equation (1) and solve to calculate the force applied on the block.

$\begin{cases}F - 50\sin 30 ° & = & 5 \times 1 \\ & ⇒ & F = \left(5 + 25\right)N \\ & = & 30N\end{cases}$

The velocity of $the block \left(v\right) at$t = 10s$can be written as</p><p>$\begin{cases}v & = & 0 + 1m{s}^{- 2} \times 10s \\ & = & 10m{s}^{- 1}\end{cases}$</p><p>Hence,$ the $required power is given by</p><p>$\begin{cases}P & = & Fv \\ & = & 30N \times 10m{s}^{- 1} \\ & = & 300W\end{cases}$$