Question

A 1000 kg car is moving along a level highway with a speed of 10 m/s. The driver takes her foot off the gas, and the car experiences a friction force of 500 N over a distance of 25 m. Determine the final speed of the car.

a) 5 m/s
b) 6 m/s
c) 7 m/s
d) 8 m/s

Answer 1

The final speed of the car is 7 m/s. Option C is correct.

Step-by-step explanation:

We can use the following equation to solve for the final speed of the car:

v^2 = u^2 + 2as

where:

• v is the final speed
• u is the initial speed
• a is the acceleration
• s is the distance

The acceleration of the car can be calculated using the following equation:

a = F/m

where:

• F is the force
• m is the mass

Plugging in the values we know, we get:

a = -500 N / 1000 kg = -0.5 m/s^2

The negative sign indicates that the acceleration is in the opposite direction of the car's motion.

Plugging in the values we know, we get:

v^2 = 10 m/s^2 + 2 (-0.5 m/s^2) (25 m)

v^2 = 45 m/s^2

Taking the square root of both sides, we get:

v = 6.7 m/s

Rounding to the nearest meter, we get:

v = 7 m/s

Therefore, the final speed of the car is 7 m/s (Option C).