A car of mass 1000 kg is moving with a velocity of 20 m/s. If the brakes are applied and the car comes to a stop in 5 seconds, what is the average force applied by the brakes?
Practice Questions
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Q1
A car of mass 1000 kg is moving with a velocity of 20 m/s. If the brakes are applied and the car comes to a stop in 5 seconds, what is the average force applied by the brakes?
2000 N
4000 N
5000 N
6000 N
The change in momentum is 1000 kg * 20 m/s = 20000 kg·m/s. The average force is F = Δp/Δt = 20000 kg·m/s / 5 s = 4000 N.
Questions & Step-by-step Solutions
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Q
Q: A car of mass 1000 kg is moving with a velocity of 20 m/s. If the brakes are applied and the car comes to a stop in 5 seconds, what is the average force applied by the brakes?
Solution: The change in momentum is 1000 kg * 20 m/s = 20000 kg·m/s. The average force is F = Δp/Δt = 20000 kg·m/s / 5 s = 4000 N.
Steps: 7
Step 1: Identify the mass of the car, which is 1000 kg.
Step 2: Identify the initial velocity of the car, which is 20 m/s.
Step 3: Calculate the initial momentum of the car using the formula: momentum = mass * velocity. So, momentum = 1000 kg * 20 m/s = 20000 kg·m/s.
Step 4: Determine the final velocity of the car after it stops, which is 0 m/s.
Step 5: Calculate the change in momentum (Δp) by subtracting the final momentum from the initial momentum. Δp = initial momentum - final momentum = 20000 kg·m/s - 0 kg·m/s = 20000 kg·m/s.
Step 6: Identify the time taken to stop the car, which is 5 seconds.
Step 7: Calculate the average force (F) applied by the brakes using the formula: F = Δp / Δt. So, F = 20000 kg·m/s / 5 s = 4000 N.
