A box weighing 2.4 x 10^2 Newton's is lifted at a constant speed to a shelf 1.2 meters high in 4.0 seconds. What power is requir
1 answer:
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Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:
where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.
Answer:
The weight of measuring stick is 9.8 N
Explanation:
given information:
the mass of the rock, = 1 kg
measuring stick, x =1 m
d = 0.25 m
to find the weight of measuring stick, we can use the following equation:
τ = Fd
τ = 0
-
= 0
F_{r} = the force of the rock
F_{s} = the force of measuring stick
= m g
= 1 kg x 9.8 m/s
= 9.8 N
thus, the weight of measuring stick is 9.8 N