Question

Physics help question 4?

A building under construction requires building materials to be raised to the upper floors by cranes or elevators. An amount of cement is lifted 86.3 m by a crane, which exerts a force on the cement that is slightly larger than the weight of the cement. If the network done on the cement is 1.89 X 103 J, what is the magnitude of the net force exerted on the cement?

Answer 1

The force on the cement must have been 21.9 N

Explanation:

The relation between work done, force exerted and displacement is

`W=F*d`

so, the force exerted to do the work must be

#F=W/d = (1.89xx10^3J)/86.3 m = 21.9 N

Answer 2

Force = `21.9 N`

Explanation:

Force = `21.9 N`
We’re essentially looking at the energy input required to equal a potential energy difference of 86.3m. The SI unit of work is the joule (J), dimensionally: `1 kg*m^2/s^2`.
Work = Force x Distance
Force = `(1.89 xx 10^3)/86.3 = 21.9 N`