Answer:
V = 3.54 m/s
Explanation:
Using the conservation of energy:

so:

where w is te weigh of kelly, h the distance that kelly decends, m is the mass of kelly and V the velocity in the lowest position.
So, the mass of kelly is:
m = 425N/9.8 = 43.36 Kg
and h is:
h = 1m-0.36m =0.64m
then, replacing values, we get:

Solving for v:
V = 3.54 m/s
Answer:
C
Explanation:
light can travel in a vacuum Anne the sped varies
Answer:
Current, I = 1000 A
Explanation:
It is given that,
Length of the copper wire, l = 7300 m
Resistance of copper line, R = 10 ohms
Magnetic field, B = 0.1 T

Resistivity, 
We need to find the current flowing the copper wire. Firstly, we need to find the radius of he power line using physical dimensions as :




r = 0.00199 m
or

The magnetic field on a current carrying wire is given by :



I = 1000 A
So, the current of 1000 A is flowing through the copper wire. Hence, this is the required solution.
Answer:
Answered
Explanation:
The radius of curvature of the mirror R = 20 cm
then the focal length f = R/2 = 10 cm
(a) From mirror formula
1/f = 1/di + /1do
then the image distance
di = fd_o / d_o - f
= (10)(40) / 40-10
= 30.76 cm
since the image distance is positive so the image is real
ii) when the object distance d_0=20 cm
di = 10×20/ 20-10
= 20
Hence, the image must be real
iii)when the object distance d_0 = 10
di = 10×10 / 10-10 = ∞ (infinite)
the image will be formed at ∞
here also image will be real but diminished.
There is kinetic energy when it is sitting at the top, then as it goes towards the bottom, the kinetic energy is transformed into potential energy.