Calculating Power for a Coasting Car with Given Equation and Values | 1072 kg

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In summary, the conversation discusses a car with a mass of 1072 kg that is coasting on a straight, level road. Its speed as a function of time is given by the equation v(t) = a - bt + ct^2. At a time of 38.0 s, the speed is 18.05 m/s. The problem is to calculate the power needed to maintain that speed, taking into account air resistance and rolling resistance. The suggested approach is to use Newton's second law and the equation for power required to maintain a constant velocity.
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melito
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A car with a mass of 1072 kg is coasting in neutral on a straight,level road. It slows down, and its speed as a function of time is given by the equation:
v(t) = a − bt + ct2



Constant Value Units
a 26.8 m/s
b 0.310 m/s2
c 2.10·10^-3 m/s2

At a time of 38.0 s the speed, as given by the above equation, is 18.05 m/s. Calculate the power which the engine must deliver (to compensate for air resistance and rolling resistance) in order to maintain that speed.

This is the problem; but I couldn't solve it. Please help.
 
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Have you made an attempt at a solution (per Forum rules)? Try using Newton's second law to find the force acting on the car after 38 seconds, then recognize that the car moves at constant velocity thereafter , and use the equation for power required to maintain that speed. Please list the relevant equations. And welcome to PF!:smile:
 

What causes a car to slow down?

A car can slow down due to a variety of factors, including engine problems, brake issues, or a decrease in speed due to road conditions or traffic.

How do I slow down my car in a safe manner?

To slow down your car safely, you should gradually release pressure on the accelerator pedal and apply gentle pressure on the brake pedal. It is important to maintain control of your vehicle and be aware of your surroundings while slowing down.

Why is it important to slow down a car?

Slowing down a car is important for the safety of both the driver and others on the road. It allows for better control of the vehicle and reduces the risk of accidents or collisions.

Can I use the gears to slow down my car?

Yes, you can use the gears to slow down your car. Downshifting to a lower gear can help slow down the car without relying solely on the brakes, which can cause them to overheat and wear out faster.

How can I maintain a consistent speed while driving?

To maintain a consistent speed while driving, you can use cruise control (if your car has it) or avoid constantly accelerating and braking by anticipating traffic and road conditions and adjusting your speed accordingly.

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