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:

A concave mirror is opaque whereas a concave lens is transparent. ... Difference between concave mirror and concave lens is A concave mirror is opaque whereas a concave lens is transparent. A concave mirror causes reflection of light whereas a concave lens causes refraction of light.
Answer:
Magnetic field, B = 0.23 T
Explanation:
Given that,
Length of the copper rod, L = 0.49 m
Mass of the copper rod, m = 0.15 kg
Current in rod, I = 13 A (in +ve y direction)
When the rod is placed in magnetic field, the magnetic force is balanced by its weight such that :

So, the magnitude of the minimum magnetic field needed to levitate the rod is 0.23 T.
Answer:
v₁ = 2.48m/s, v₂ = 0.02m/s
Explanation:
Momentum p must be conserved. p = mv
1) First person throwing the snow ball. The momentum before the throw:
p = (65kg + 0.045kg) * 2.5 m/s
The momentum after the throw:
p = 65kg * v₁ + 0.045kg * 30m/s
Solving for the velocity v₁ of person 1:
v₁ = ((65kg + 0.045kg) * 2.5 m/s - 0.045kg * 30m/s) / 65kg = 2.48m/s
2) Second person catching the ball. The momentum before the catch:
p = 0.045kg * 30m/s + 60kg * 0m/s
The momentum after the catch:
p = (60kg + 0.045kg) * v₂
Solving for velocity v₂ of person 2:
v₂ = 0.045kg * 30m/s / (60kg + 0.045kg) = 0.02 m/s
Answer:
Parallel circuit
Explanation:
A parallel circuit is a closed circuit in which current flows and divide in two or more paths and recombining to complete the circuit, each load (light bulb) receives the fully voltage of the batteries in the circuit.