A motor car is moving with a velocity of 100 kilometre by our and it t...
Initial velocity of motar car u=108
=108×1000m/60×60s
=30ms
the total mass of the motor car along with its passenger =1000 kg e and the time taken to stop the motor car =4s
F=v-u/t
F=1000kg×0-30ms/4s
=-7500N
the negative sign tells us that the force exerted by the brakes is opposite to the direction of motion of the motor car
A motor car is moving with a velocity of 100 kilometre by our and it t...
Calculation of Force Exerted by the Brakes on the Motor Car
Given:
- Velocity of the motor car = 100 km/h (or 100 km/hour)
- Time taken to stop after applying brakes = 4 seconds
- Mass of the motor car along with passengers = 1000 kg
Step 1: Convert Velocity from km/h to m/s
- We need to convert the velocity from kilometers per hour to meters per second, as the SI unit for velocity is m/s.
- 1 km = 1000 m
- 1 hour = 3600 seconds
- Velocity in m/s = (100 km/h) * (1000 m/km) / (3600 s/h) = 27.78 m/s
Step 2: Calculate the Deceleration
- Deceleration is the rate at which the velocity decreases.
- Deceleration = Change in Velocity / Time
- Change in Velocity = Initial Velocity - Final Velocity (since the car is coming to a stop)
- Change in Velocity = 27.78 m/s - 0 m/s = 27.78 m/s
- Deceleration = (27.78 m/s) / (4 s) = 6.945 m/s^2
Step 3: Calculate the Force
- Force = Mass * Acceleration
- Acceleration is the negative value of deceleration since it acts in the opposite direction of velocity.
- Acceleration = -6.945 m/s^2
- Force = (1000 kg) * (-6.945 m/s^2) = -6945 N (Newton)
Step 4: Interpretation of Negative Sign
- The negative sign indicates that the force exerted by the brakes is in the opposite direction of the car's motion, which is necessary to bring the car to a stop.
Conclusion
The force exerted by the brakes on the motor car is calculated to be -6945 N. This means that the brakes apply a force of 6945 N in the opposite direction of the car's motion, causing it to decelerate and eventually come to a stop within 4 seconds.
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