A 1200 kg car on a horizontal surface starts from rest and accelerates uniformly to 72 km/h in 20.0 s. Friction exets an average force of 450 N on the car during this time.
a) what is the net work done on the car
b) how far does the car move during this acceleration
c) what is the net force exerted on the car during this time
d) what is the forward force exerted on the car as an engine, power train, and wheels pushing back on the road
help! i tried figuring it out and i get so stuck
Iwish Icould Help Im In 11th Grade Also An Ithought Yhu Had The Answer... Sorrie:(
No problem! I'll break down each part of the question and guide you through the steps to find the answers.
a) To find the net work done on the car, we need to calculate the work done by the net force. The net force can be determined by subtracting the force of friction from the force needed to accelerate the car.
The force needed to accelerate the car can be calculated using Newton's second law: F = ma, where F is the force, m is the mass, and a is the acceleration. Rearranging the equation to solve for force, we get F = ma. Plugging in the given values, we have F = (1200 kg) * (72 km/h) / (20.0 s). Note that we need to convert the speed from km/h to m/s to use SI units, so the equation becomes F = (1200 kg) * (20 m/s) / (20.0 s).
Next, we need to calculate the work done by the force of friction. The work done by friction can be found using the equation: work = force * distance. Given that the average force of friction is 450 N and we are looking for the net work, we need to subtract the work done by friction from the work done by the net force.
b) The distance covered by the car during the acceleration can be determined using the equation for average velocity: distance = velocity * time. In this case, the average velocity can be calculated by dividing the final velocity (72 km/h) by 2, as the car is starting from rest and reaching this final velocity. After converting the average velocity to m/s, the distance covered can be calculated.
c) The net force exerted on the car during this time is the sum of the force needed to accelerate the car and the force of friction.
d) The forward force exerted on the car as an engine, power train, and wheels pushing back on the road can be found using the equation: force = mass * acceleration.
Now let's calculate the answers step by step:
a) Net work done on the car:
Net force = (1200 kg) * (20 m/s) / (20.0 s)
Work done by the net force = Net force * Distance
Work done by friction = 450 N * Distance
Net work done = Work done by the net force - Work done by friction
b) Distance covered during acceleration:
Average velocity = (0 km/h + 72 km/h) / 2
Convert average velocity to m/s
Distance = Average velocity * Time
c) Net force exerted on the car:
Net force = Force needed to accelerate + Force of friction
d) Forward force exerted by the car:
Force = Mass * Acceleration
Now plug in the values for each part and perform the calculations to find the answers.