A glider of mass 0.170 kg moves on a horizontal frictionless air track. It is permanently attached to one end of a massless hori
1 answer:
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Assuming the driver starts slamming the brakes immediately, the car moves by uniformly decelerated motion, so we can use the following relationship
(1)
where
a is the deleceration
S is the distance covered after a time t
is the velocity at time t
is the initial speed of the car
The accident is 80 m ahead of the car, so the minimum deceleration required to avoid the accident is the value of a such that S=80 m and
(the car should stop exactly at S=80 m to avoid the accident). Using these data, we can solve the equation (1) to find a:
And the negative sign means it is a deceleration.
where
a is the deleceration
S is the distance covered after a time t
The accident is 80 m ahead of the car, so the minimum deceleration required to avoid the accident is the value of a such that S=80 m and
And the negative sign means it is a deceleration.
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