Answer:
applying 1st eq of motion vf=vi+at we have to find a=vf-vi/t here a=50-30/2=10 so we got a=10m/s²
Answer:
The minimum compression is 
Explanation:
From the question we are told that
The mass of the block is 
The spring constant is 
The coefficient of static friction is 
For the the block not slip it mean the sum of forces acting on the horizontal axis is equal to the forces acting on the vertical axis
Now the force acting on the vertical axis is the force due to gravity which is mathematically given as

And the force acting on the horizontal axis is force due to the spring which is mathematically represented as

where x is the minimum compression to keep the block from slipping
Now equating this two formulas and making x the subject

substituting values we have


Answer:
The answer is A because the equation is KEi+PEi=KEf+PEf
i means initial (before) and f means final (after)
Answer:
208.33 W
141.26626 seconds
Explanation:
E = Energy = 
t = Time taken = 8 h
m = Mass = 2000 kg
g = Acceleration due to gravity = 9.81 m/s²
h = Height of platform = 1.5 m
Power is obtained when we divide energy by time

The average useful power output of the person is 208.33 W
The energy in the next part would be the potential energy
The time taken would be

The time taken to lift the load is 141.26626 seconds