Answer: 100cm
Explanation:
The force of friction on a surface normal to gravity where µ is the coefficient of friction is
F = µmg
Where
F = the friction force
µ = coefficient of friction
m = mass of the object
g = acceleration due to gravity
Also, the Kinetic Energy of the object, E = Fs, where
E = Kinetic Energy
s = stopping distance. So that,
E = µmgs
40 J = 0.4 * 10 kg * 10 m/s² * s
40 J = 40 kgm/s² * s
s = 40 J / 40 kgm/s²
s = 1 m or 100 cm
C.
Newton’s Second Law is F=ma (force is equal to the mass multiplied by acceleration), however, the equation can be rearranged to isolate and calculate mass from force over acceleration. Therefore, m=F/a
Clever problem.
We know that the beat frequency is the DIFFERENCE between the frequencies of the two tuning forks. So if Fork-A is 256 Hz and the beat is 6 Hz, then Fork-B has to be EITHER 250 Hz OR 262 Hz. But which one is it ?
Well, loading Fork-B with wax increases its mass and makes it vibrate SLOWER, and when that happens, the beat drops to 5 Hz. That means that when Fork-B slowed down, its frequency got CLOSER to the frequency of Fork-A ... their DIFFERENCE dropped from 6 Hz to 5 Hz.
If slowing down Fork-B pushed it CLOSER to the frequency of Fork-A, then its natural frequency must be ABOVE Fork-A.
The natural frequency of Fork-B, after it gets cleaned up and returns to its normal condition, is 262 Hz. While it was loaded with wax, it was 261 Hz.
Answer:
The same amount of energy is required to either stretch or compress the spring.
Explanation:
The amount of energy required to stretch or compress a spring is equal to the elastic potential energy stored by the spring:
where
k is the spring constant
is the stretch/compression of the spring
In the first case, the spring is stretched from x=0 to x=d, so
and the amount of energy required is
In the second case, the spring is compressed from x=0 to x=-d, so
and the amount of energy required is
so we see that the amount of energy required is the same.
