You stand on a bathroom scale in a moving elevator. what happens to the scale reading if the cable holding the elevator suddenly
2 answers:
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Answer:
Explanation:
As per work energy theorem we know that work done by all the forces must be equal to change in kinetic energy of the car
So here when brakes are applied then work is done by the brakes which is equal to change in kinetic energy of the car
so we know that work done by the brakes is given as
now we will have
Answer:
a. Vf = 39.24 [m/s]
b. Vf = 31.24 [m/s]
c. Vf = 47.24 [m/s].
Explanation:
To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (when the rock is dropped)
g = gravitational acceleration = 9.81 [m/s²]
t = time = 4 [s]
a.
b.
In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.
The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.
c.