Answer:
a. 652.68N
b. -2349.65J
c. -3116.12J
d. 5465.77J
e. Zero
Explanation:
a. According to equilibrium of forces, the force of gravity is equal to the sum of the frictional force and force exerted by the man in the opposite direction (since they're both resistant forces).
Fg = Fm + Fr
Fm = Fg - Fr
Fm = mgsin(28°) - umgcos(28°)
u = coefficient of frictional force.
Fm = 330*9.8*sin28 - 0.4*330*9.8*cos28
Fm = 1518.27 - 865.59
Fm = 652.68N
b. Work done by man is:
Wm = -Fm * d
Wm = -652.68 * 3.6
Wm = -2349.65J
c. Work done by friction force:
W(Fr) = -Fr * d
W(Fr) = -865.59 * 3.6
W(Fr) = -3116.12J
d. Work done by gravity:
Wg = Fg * d
Wg = 1518.27 * 3. 6
Wg = 5465.77J
e. Net work done on the piano is:
Work done by friction + work done by gravity + work done by man
= -3116.12 + 5464.77 + (-2349.65)
= 0J
Answer:
A mother with gestational diabetes decides to limit her sugar intake.
Explanation:
The coefficient of restitution is a measure of the interaction of the ball with the material of the ground. Since the ground is too solid to move (usually), or give way, the energy of the ball-ground system must be conserved in the main. Some of the energy is released as sound waves but the rest is given to, or reflected back to the ball and it follows the path of reflection. When the ball is dropped vertically it returns along the same path. So the force is actually the potential energy created by dropping converted to kinetic energy on collision with the ground. This is the origin of the force making it bounce.
Because ot helps us to do our work. it is the capacity of doing work. the energy like mechanical energy, chemical energy etc have been helping humans from almost origin of our life. transformation of energy also helps us grately. in this way energy is essential to our way of life.
Answer: 529.9 Hz
Explanation:
Here we need to use the Doppler equation, so we have:
f' = f*(v + v0)/(v - vs)
Here, f is the frequency = 500Hz
v is the velocity of the wave, = 334m/s
v0 is the velocity of the observer = 20m/s
vs is the velocity of the source = 0m/s
Then we have:
f' = 500Hz*(334m/s + 20m/s)/(334m/s) = 529.9 Hz