Answer:
(a) 21.36 ohms
(b) 5.62 A
Explanation:
Parameters given:
Potential difference, V = 120 V
Power, P = 674 W
(a) Power is given as:
P = V²/R
Where R is resistance
=> R = V²/P
R = 120²/674
R = 14400/674
R = 21.36 ohms
(b) Power is also given as:
P = I*V
Where I = Current (time rate of flow of Electric charge)
=> I = P/V
I = 674/120
I = 5.62 A
Answer:
K.E = 100 J
Final P.E = 100 J
Explanation:
The kinetic energy of any object can be given by the following formula:

where,
K.E = Kinetic Energy
m = mass of ball = 2 kg
v = speed of ball
Initially, v = 10 m/s. Therefore, the initial K.E is given as:

<u>K.E = 100 J</u>
Now, at the highest point the K.E of the ball becomes zero. because the ball stops for a moment at the highest point and its velocity becomes zero. So, from Law of Conservation of energy:
Initial K.E + Initial P.E = Final K.E + Final P.E
Initial P.E is also zero due to zero height initially.
K.E + 0 = 0 + Final P.E
<u>Final P.E = 100 J</u>
It would be 1. B 2. A 3. A
Answer
given,
mass of the crate = 53 Kg
force applied by the worker = 180 N
Angle made with the horizontal = 35°
crate moves = 2.9 m
a) The work done equals the force in the direction of the displacement, times the displacement
W = F_x ×d
W = 180 cos 35° × 2.9
W = 427.6 J
b) A force that is perpendicular to the direction of the displacement does not do any work so work done by gravitational force is zero
c) Similarly for the normal force the work done will be zero.
d) Total work done by the crate is equal to 427.6 J