Answer:
- 80 Ns
Explanation:
The complete statement is given as
A sled and rider, gliding over horizontal, friction less ice at 4.0 m/s, have a combined mass of 80 kg. The sled then slides over a rough spot in the ice, slowing down to 3.0 m/s. What impulse was delivered to the sled by the friction force from the rough spot?
[tex]v_{i}[/tex] = initial velocity of the sled = 4.0 m/s
[tex]v_{f}[/tex] = final velocity of the sled = 3.0 m/s
[tex]m[/tex] = combined mass of sled and rider = 80 kg
[tex]I[/tex] = Impulse delivered to sled
Using Impulse-change in momentum equation, Impulse delivered to sled is given as
[tex]I = m (v_{f} - v_{i})\\I = (80) (3 - 4)\\I = - 80 Ns[/tex]
