contestada

A certain motor is able to pull a 20 kg block across a frictionless floor, increasing its speed from 10 m/s to 12 m/s in 4 seconds.At what rate is work done by this motor?

Respuesta :

2844519

Answer:

The work done by the motor is equal to the change in kinetic energy of the block. The kinetic energy (KE) is given by the formula KE=21​mv2

where m is the mass and v is the velocity.

The change in kinetic energy is then:

ΔKE=KEfinal​−KEinitial​=21​m(vfinal2​−vinitial2​)

Substituting the given values:

ΔKE=21​×20kg×((12m/s)2−(10m/s)2)=400J

The rate of work done, or power, is the work done per unit time. So, the power P is given by:

P=ΔtΔKE​

Substituting the given values:

P=4s400J​=100W

So, the motor is doing work at a rate of 100 Watts.