Question

If the contact surface between the 20-kg block and the ground is smooth, determine the power of force F when t = 4 s. Initially, the block is at rest

Answer 1

The power of force F is 115.2 W

Step-by-step explanation:

Use following formula

Power = F x V

`F_(H)` = F cos0

`F_(H)` = (30) x 4/5

`F_(H)` = 24N

Now Calculate V using following formula

V =
`V_(0)` + at

`V_(0)` = 0

a =
`F_(H)` / m

a = 24N / 20 kg

a = 1.2m /
`S^(2)`

no place value in the formula of V

V = 0 + (1.2)(4)

V = 4.8 m/s

So,

Power =
`F_(H)` x V

Power = 24 x 4.8

Power = 115.2 W