Answer:
h = 20 m
Explanation:
Given that,
Force to lift a firefighter's equipment, F = 270 N
Work done, W = 5400 J
We need to find the height climbed by the firefighter. We know that,
Work done, W = Fd
So,
So, the firefighter climb from a height of 20 m.
The final speed of the crate is 6.3 m/s
Explanation:
Please note that there is a typo in the text of the question: the coefficient of sliding friction is 0.15, not 9.15.
First of all, we need to find the force of friction acting on the crate. This is given by:
where:
is the coefficient of friction
m = 50 kg is the mass of the crate
is the acceleration of gravity
Substituting,
Now we can find the acceleration of the crate by using Newton's second law:
where
F = 90.0 N is the force applied forward on the crate
is the force of friction, acting backward
a is the acceleration of the crate
Solving for a,
in the forward direction.
Finally, we can find the final speed of the crate by using suvat equations:
where:
v is the final speed
u = 0 is the initial speed
is the acceleration
s = 60 m is the distance covered
Solving for v,
Learn more about friction, forces and Newton's second law here:
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