How much work must be done on a 750 kg car to slow it down from 1.0 x 10 km/h to 2 50.0 km/h?
1 answer:
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Answer:
9.43 m/s
Explanation:
First of all, we calculate the final kinetic energy of the car.
According to the work-energy theorem, the work done on the car is equal to its change in kinetic energy:
where
W = -36.733 J is the work done on the car (negative because the car is slowing down, so the work is done in the direction opposite to the motion of the car)
is the final kinetic energy
is the initial kinetic energy
Solving,
Now we can find the final speed of the car by using the formula for kinetic energy
where
m = 661 kg is the mass of the car
v is its final speed
Solving for v, we find
From the theory we know that:
c = λ / T
f = 1 / T
Where:
c = 3. / m (the speed of light)
λ is the wavelengh (in meters)
T is the period (in seconds)
f is the frequency (in Hz)
We were told that:
f = 7.30 .
And we want to find out the value of λ.
c = λ / T
c = λ . 1/T
Swaping 1/T = f
c = λ . f
λ = c / f
λ = 3 . / 7.30 .
λ = 4.12 m
Response: 4.12 m = 412 nm
:-)