Answer:

Explanation:
The density changes means that the length in the direction of the motion is changed.
Therefore,

Given :
Side, b = h = 0.13 m
Mass, m = 3.3 kg
Density = 8100 
So,


l = 0.024 m
Then for relativistic length contraction,







Therefore, the speed of the observer relative to the cube is 0.9833 c (in the units of c).
Answer:
Workdone = 20 Joules
Explanation:
Given the following data;
Force = 10N
Extension, e = 4cm to meters = 4/100 = 0.04 meters
Workdone extension = 40cm to meters = 40/100 = 0.4 meters
To find the work done;
First of all, we would find the spring constant using the formula;
Force = spring constant * extension
10 = spring constant * 0.04
Spring constant = 10/0.04
Spring constant = 250 N/m
Next, we find the work done;
Workdone = ½ke²
Where;
k is the spring constant.
e is the extension.
Substituting into the formula, we have;
Workdone = ½ * 250 * 0.4²
Workdone = 125 * 0.16
Workdone = 20 Joules
Answer:
The power dissipated by the meter is 1188W
Explanation:
Here we have a circuit constituted with a power source and two resistors in series, we can calculate the power dissipated by the meter using the following formula:
We first need to fin the current going through the circuit:
because they are connected in series. So:
Answer: 2.37N
Explanation:
According to coulombs law which states that the force of attraction (F) between two charges (q1 and q2) is directly proportional to the product of their charges and inversely proportional to the square of the distance (r) between them. Mathematically,
F = kq1q2/r²
For the first two charges that are sitting 1.5 m apart with a force of 3 N between them, we have
3 = kq1q2/1.5²
3 = kq1q2/2.25
Kq1q2= 6.75... (1)
If the charges are now moved farther apart 2.25 m and one of the charges is increased by a factor of 4. The formula becomes
F2 = k(4q1)q2/2.25² (q1 has been increased by factor of 4)
k(4q1)q2 = 5.06F2 ... (2)
Dividing 2 by 1 we have
k(4q1)q2/kq1q2 = 5.06F2/3
4 = 5.06F2/3
5.06F2 = 12
F2= 12/5.06
F2 = 2.37N
Therefore the magnitude of the new force between the two charges is 2.37N
Answer:
Option (A)
Explanation:
Displacement of a particle on a velocity time graph is represented by the area between the line representing velocity and x-axis (time).
Displacement of a particle from t = 0 o t = 40 seconds = Area of ΔAOB
Area of triangle AOB = 
= 
= 80 m
Similarly, displacement of the particle from t = 40 to t = 80 seconds = Area of ΔBCD
Area of ΔBCD = 
= 80 m
Total displacement of the particle from t = 0 to t = 80 seconds,
= 80 + 80
= 160 m
Option (A) will be the answer.