Reflection on Calculating Force to Bring Car to Rest

What is the force required to bring a car of mass 1200 kg to rest in 5 seconds?

1) 480 N

2) 4.8 N

3) -4800 N

4) 6000 N

Final answer:

The force required to bring the car to rest is -4800 N.

Reflecting on the question of calculating the force required to bring a car of mass 1200 kg to rest in 5 seconds leads us to understand the concept of deceleration and Newton's second law of motion.

Newton's second law of motion states that force (F) is equal to mass (m) multiplied by acceleration (a). In this case, the car has a mass of 1200 kg and needs to come to rest, which means it will experience deceleration.

To calculate the force required, we first determine the acceleration of the car. The initial velocity of the car is given as 20 m/s, and it needs to come to rest in 5 seconds. Therefore, the acceleration will be -4 m/s² (negative sign indicates deceleration).

Using the formula F = m * a, where F is the force, m is the mass, and a is the acceleration, we can plug in the values to find the force required: F = (1200 kg) * (-4 m/s²) = -4800 N.

Therefore, the force required to bring the car to rest is -4800 N. Option 3) -4800 N is the correct answer.