Answer:

Explanation:
l = Length of ladder = 8.57 m
m = Mass of ladder = 21.4 kg
F = Force on ladder = 258 N
= Angular acceleration = 
g = Acceleration due to gravity = 
Net torque is given by

The net torque acting on the ladder is
.
Answer:
0.536 A
Explanation:
From the question,
The combined resistance of the parallel connection is given as
1/Rt = 1/4+1/6+1/10
Rt = 120/15
Rt = 8 ohms.
Since the the combination is connected in series with a 10 ohms resistor,
Rt' = 8+10 = 18 ohms.
Current flowing through the series circuit
I = V/Rt'
V = 12 V, Rt' = 18 ohms
I = 12/18
I = 0.67 A.
Therefore voltage across the combined resistor
V' = 8(0.67)
v' = 5.36 V.
Since the resistors a connected in parallel, the same voltage drop across them.
Therefore, current through the 10 ohms
Ix = 5.36/10
Ix = 0.536 A
Answer:
Part a)
Work done is given as
W = -121.5 J
Part b)
Potential energy of the system is given as

Explanation:
As we know that work done by variable force is given as

here we know that

so we have

so we have

here we displace it from x = 2 to x = 5
so we will have


Part b)
As we know that change in Potential energy = work done



Fe/Fr I think hope this helps