Answer:
197 hits/s
Explanation:
If the record is turning at the rate of 33 rev/min that means it's turning
If the groove is being played at radius of 10 cm (or 0.1m), that means the record is rotating with the speed of:
The goove bumps is uniformly separated at 1.75 mm(or 0.00175m/bump) bumps. So the number of hits per second it should be
Answer:
option D
Explanation:
given,
uniform length of cylinder = 1 m
diameter of the cylinder = 10 cm = 0.1 m
Eels have been recorded to spin = 14 rev/s
camera records at = 120 frames per second
time =
angle at which eel rotate = ?
ω = 14 rev/s
ω = 14 x 2 π rad/s
ω = 28 π rad/s
angle at which eel rotate
θ = ω t
θ =
θ = 0.733 rad
θ =
θ =
Hence, the correct answer is option D
Answer:
<em>Both energies are equal when the rock has fallen 20 m or equivalently when it is at a height of 20 m.</em>
Explanation:
<u>Potential and Kinetic Energy</u>
The gravitational potential energy is the energy an object has due to its height above the ground. The formula is
Where:
m = mass of the object
g = acceleration of gravity (9.8~m/s^2)
h = height
Note we can also use the object's weight W=mg into the formula:
The kinetic energy is the energy an object has due to its speed:
Where v is the object's speed.
Initially, the object has no kinetic energy because it's assumed at rest.
The W=30 N rock falls from a height of h=40 m, thus:
Since the sum of the kinetic and potential energies is constant:
U' + K' = 1,200 J
Here, U' and K' are the energies at any point of the motion. Since both must be the same:
U' = K' = 600 J
U'=Wh'=600
Solving for h':
Both energies are equal when the rock has fallen 20 m or equivalently when it is at a height of 20 m.