Work = (force) x (distance)
If the distance is zero (the object doesn't move), then it
doesn't matter how great the force is. The work is still zero.
Answer: 750 N
Explanation:
The net force is 1200 - 450 = 750 N
As we are told the speed is constant, then this force must be increasing the car's potential energy by climbing a hill.
F = mgsinθ
If we knew the car mass, we could find the hill slope angle.
If we knew the hill slope angle, we could find the car mass.
Answer:

Explanation:
As we know that thermal expansion coefficient of aluminium is given as

now we also know that after thermal expansion the final length is given as

here we know that



now we will have


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.
First we have to calculate the volume of the living room:
V = L x W x H = 4.5 m * 3.4 m * 2.9 m
V = 44.37 m³
We know that Density = 1.29 kg/m²
D = m / V
m = D · V
m = 1.29 kg/m³ · 44.37 m³
m = 57.2373 kg ≈ 57.2 kg
Answer: The approximate mass of air in living room is 57.2 kg.