Question

A 520kg rocket sled at rest is propelled along the ice by an engine developing a constant thrust of 12 000 N over a distance of 40 m. Assuming all of the work goes into motion, calculate a). The work done by the engine on the sled after 40 m b). Its velocity after 40 m (using the kinetic energy formula).​

Answer 1

a) 480 000 J

b) 43 m/s

Step-by-step explanation:

a)

To calculate the work done by the engine, we can use the following formula:

`\boxed{\mathrm{Work \space\ done = Force * Distance}}`.

⇒
`12000 * 40`

⇒
`480000 \space\ \mathrm J`

b)

We know that the work done by the propeller was converted into motion of the sled, which means the propeller provided the sled with kinetic energy.

∴ work done by propeller = kinetic energy gained by sled

⇒
`480000 = (1)/(2) mv^2`

⇒
`480000 = (1)/(2) * 520 * v^2`

⇒
`480000 = 260v^2`

⇒
`v^2 = (480000)/(260)`

⇒
`v =\bf 43 \space\ m/s`

This means that its velocity after 40 m was 43 m/s.