(a) The momentum of the first trolley is 5.4 kgm/s
(b) The velocity of the trolleys after impact is 2.7m/s
<u>Explanation:</u>
Given:
Mass, m₁ = 1.2kg
Velocity, v₁ = 4.5m/s
Mass, m₂ = 0.8kg
v₂ = 0
(a) Momentum of the trolley before impact, p
We know:
Momentum = mass X velocity
p = 1.2 X 4.5
p = 5.4 kgm/s
Therefore, the momentum of the first trolley is 5.4 kgm/s
(b) Speed of the trolleys after impact, v = ?
During collision, the momentum is conserved.
So,
m₁v₁ + m₂v₂ = (m₁ + m₂)v
(1.2 X 4.5) + (0.8 X 0) = (1.2 +0.8) X v
5.4 + 0 = 2v
v = 2.7m/s
Therefore, the velocity of the trolleys after impact is 2.7m/s
Answer: First option
Explanation: The higher the frequency, the higher the energy.
λν=c where λ is the wavelength, ν is the frequency and c is the speed of light. So when wavelength decreases, v increases and so does energy.
An AM radio wave has a very long wavelength. It therefore has a very low frequency and low energy.
A light wave has a very short wavelength. It therefore has a high frequency and high energy.
Answer:
Inductive reactance is 125.7 Ω
Explanation:
It is given that,
Inductance, 
Voltage source, V = 15 volt
Frequency, f = 400 Hz
The inductive reactance of the circuit is equivalent to the impedance. It opposes the flow of electric current throughout the circuit. It is given by :
So, the inductive reactance is 125.7 Ω. Hence, this is the required solution.
Answer:
(B) 0.5 g
Explanation:
Newton's second law says ∑ F i = m a .
the rate of change in momentum of a body is proportional to the force applied on the body.
f∝ma
f=kma
were k is constant and equal to 1
The centripetal acceleration is an acceleration.
the tension on the swing and object weight goes to the left hand side while the centripetal acceleration goes to the right handside
At the bottom of the swing, ΣF = FT – mg = mac;
notice that the tension in the swing is 1.5 times the weight of the object
we can write
1.5mg – mg = mac,
0.5mg = mac
0.5 g=ac
