A 5kg box is sliding down a ramp with a rough surface as seen below. The height of the ramp is 20m and the distance the box travels down the ramp (from A to B) is 15m. At point A the velocity of the box is 8 m/s. If the velocity at point B is 3m/s, what was the impulse caused by friction? If the force of friction is 5N, how long did it take the box to slide the 15 m?

A Impulse = – 25 Ns

B. Time = 5 s

Explanation:

From the question given above, the following data were obtained:

Mass (M) = 5 Kg

Initial velocity (u) = 8 m/s

Final velocity (v) = 3 m/s

Impulse (I) =?

Time (t) =?

A. Determination of the Impulse.

Mass (M) = 5 Kg

Initial velocity (u) = 8 m/s

Final velocity (v) = 3 m/s

Impulse (I) =?

I = Ft = M(v – u)

I = M(v – u)

I = 5 (3 – 8)

I = 5 × – 5

I = – 25 Ns

NOTE: the negative sign indicates that the net force is acting in the negative direction.

B. Determination of the time.

Impulse (I) = 25 Ns

Force (F) = 5 N

Time (t) =?

I = Ft

25 = 5 × t

Divide both side by 5

t = 25 / 5

t = 5 s

Thus, it will take 5 s for the box to slide through the 15 m long ramp.