Let's consider the following free-body diagram:

From the above diagram, it can be written that
F−mgsin30∘=ma...(1)
Substitute the values of the known parameters into equation (1) and solve to calculate the force applied on the block.
F−50sin30∘=⇒=5×1F=(5+25)N30N
The velocity of the block (v) at t=10s can be written as
v==0+1ms−2×10s10ms−1
Hence, the required power is given by
P===Fv30N×10ms−1300W