Answer:
F = 352 N
Explanation:
we know that:
F*t = ΔP
so:
F*t = M-M
where F is the force excerted by the wall, t is the time, M the mass of the ball, the final velocity of the ball and
the initial velocity.
Replacing values, we get:
F(0.05s) = (0.8 kg)(11m/s)-(0.8 kg)(-11m/s)
solving for F:
F = 352 N
Work needed: 720 J
Explanation:
The work needed to stretch a spring is equal to the elastic potential energy stored in the spring when it is stretched, which is given by
where
k is the spring constant
x is the stretching of the spring from the equilibrium position
In this problem, we have
E = 90 J (work done to stretch the spring)
x = 0.2 m (stretching)
Therefore, the spring constant is
Now we can find what is the work done to stretch the spring by an additional 0.4 m, that means to a total displacement of
x = 0.2 + 0.4 = 0.6 m
Substituting,
Therefore, the additional work needed is
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Answer:
Explanation:
We can find the resistance of the wire by using Ohm's law:
where
V is the voltage applied
R is the resistance
I is the current
In this problem, we know I = 6 A and V = 68 V, so we can re-arrange the equation to find the resistance of the wire: