a) 120 s
b) v = 0.052R [m/s]
Explanation:
a)
The period of a revolution in a simple harmonic motion is the time taken for the object in motion to complete one cycle (in this case, the time taken to complete one revolution).
The graph of the problem is missing, find it in attachment.
To find the period of revolution of the book, we have to find the time between two consecutive points of the graph that have exactly the same shape, which correspond to two points in which the book is located at the same position.
The first point we take is t = 0, when the position of the book is x = 0.
Then, the next point with same shape is at t = 120 s, where the book returns at x = 0 m.
Therefore, the period is
T = 120 s - 0 s = 120 s
b)
The tangential speed of the book is given by the ratio between the distance covered during one revolution, which is the perimeter of the wheel, and the time taken, which is the period.
The perimeter of the wheel is:
where R is the radius of the wheel.
The period of revolution is:
Therefore, the tangential speed of the book is:
Answer:
The change in the centripetal acceleration of the brother,
Δa = V₂²/R - V₁²/R
Explanation:
Given data,
A sister spins her brother in a circle of radius, R
The angular velocity of the brother, ω₁ = V₁/R
The angular velocity of the brother, ω₂ = V₂/R
The centripetal acceleration is given by the relation
a = V²/R
Therefore change in the centripetal acceleration of the brother,
Δa = V₂²/R - V₁²/R
Answer:
The magnitude of the average force exerted on the water by the blade is 960 N.
Explanation:
Given that,
The mass of water per second that strikes the blade is, 
Initial speed of the oncoming stream, u = 16 m/s
Final speed of the outgoing water stream, v = -16 m/s
We need to find the magnitude of the average force exerted on the water by the blade. It can be calculated using second law of motion as :
F = -960 N
So, the magnitude of the average force exerted on the water by the blade is 960 N. Hence, this is the required solution.
Answer:
Wycleff is on block 1, Lilly is on block 4, Emilia is on block 12, and Quincy is on block 17.
Explanation:
Wycleff was at block 1 and heard a low pitch sound the whole time, so the police car must have been moving away from him.
Lilly observed was in block 4 change in pitch first. So the car must have passed her first.
Emilia was at block 12 observed a Doppler effect after Lilly. So the car passed her after passing Lilly
Quincy was at block 17 so she heard a high pitch sound the whole time, so the police car must have been moving toward him.
