Answer:
a) 480 000 J
b) 43 m/s
Explanation:
a)
To calculate the work done by the engine, we can use the following formula:
[tex]\boxed{\mathrm{Work \space\ done = Force \times Distance}}[/tex].
⇒ [tex]12000 \times 40[/tex]
⇒ [tex]480000 \space\ \mathrm J[/tex]
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
⇒ [tex]480000 = \frac{1}{2} mv^2[/tex]
⇒ [tex]480000 = \frac{1}{2} \times 520 \times v^2[/tex]
⇒ [tex]480000 = 260v^2[/tex]
⇒ [tex]v^2 = \frac{480000}{260}[/tex]
⇒ [tex]v =\bf 43 \space\ m/s[/tex]
This means that its velocity after 40 m was 43 m/s.
