Refraction as in a pencil going into water
Answer:
114.44 J
Explanation:
From Hook's Law,
F = ke................. Equation 1
Where F = Force required to stretch the spring, k = spring constant, e = extension.
make k the subject of the equation
k = F/e.............. Equation 2
Given: F = 10 lb = (10×4.45) N = 44.5 N, e = 4 in = (4×0.254) = 1.016 m.
Substitute into equation 2
k = 44.5/1.016
k = 43.799 N/m
Work done in stretching the 9 in beyond its natural length
W = 1/2ke²................. Equation 3
Given: e = 9 in = (9×0.254) = 2.286 m, k = 43.799 N/m
Substitute into equation 3
W = 1/2×43.799×2.286²
W = 114.44 J
Answer:
P = 75 W
Explanation:
given,
Distance, L = 8 m
Force,F = 150 N
Time, t = 16 s
Work by the climber
Work done = Force x displacement
W = F. L
W = 150 x 8
W = 1200 J
We know,


P = 75 W
Hence, Power climber is using to climb is equal to 75 W.
Answer:
0.34 m/s^2
Explanation:
force=mass × acceleration
400 =1200 × acceleration
acceleration=400/1200
=0.34 m/s^2
Answer:
108.7 V
Explanation:
Two forces are acting on the particle:
- The external force, whose work is 
- The force of the electric field, whose work is equal to the change in electric potential energy of the charge: 
where
q is the charge
is the potential difference
The variation of kinetic energy of the charge is equal to the sum of the work done by the two forces:

and since the charge starts from rest,
, so the formula becomes

In this problem, we have
is the work done by the external force
is the charge
is the final kinetic energy
Solving the formula for
, we find
