Answer:
720 J
Explanation:
The gravitational potential energy that Essam loses for every metre is given by:

where
m=72 kg is Essam's mass
is the gravitational field strength
is the difference in height
By substituting the numbers into the formula, we find

Answer:
The stars are moving away from us.
Explanation:
The observed wavelengths of hydrogen transition for stars A and B (660.0 nm and 666 nm respectively) are greater than that observed in the laboratory (656.2 nm). The observed long wavelengths for the stars means that the light from the stars is red-shifted.
According to the Doppler effect, red-shifted light means that the source is moving a way from the observer; therefore, we arrive at the conclusion that the stars A and B are moving away from us.
Let
be the direction the swimmer must swim relative to east. Then her velocity relative to the water is

The current has velocity vector (relative to the Earth)

The swimmer's resultant velocity (her velocity relative to the Earth) is then


We want the resultant vector to be pointing straight north, which means its horizontal component must be 0:

which is approximately 41º west of north.
Answer:

Explanation:
Given:
- initial gauge pressure in the container,

- atmospheric pressure at sea level,

- initial volume,

- maximum pressure difference bearable by the container,

- density of the air,

- density of sea water,

<u>The relation between the change in pressure with height is given as:</u>

where:
dz = height in the atmosphere
= standard value of gravity
<em>Now putting the respective values:</em>



Is the maximum height above the ground that the container can be lifted before bursting. (<em>Since the density of air and the density of sea water are assumed to be constant.</em>)
Answer:
3.5 cm
Explanation:
mass, m = 50 kg
diameter = 1 mm
radius, r = half of diameter = 0.5 mm = 0.5 x 10^-3 m
L = 11.2 m
Y = 2 x 10^11 Pa
Area of crossection of wire = π r² = 3.14 x 0.5 x 10^-3 x 0.5 x 10^-3
= 7.85 x 10^-7 m^2
Let the wire is stretch by ΔL.
The formula for Young's modulus is given by


ΔL = 0.035 m = 3.5 cm
Thus, the length of the wire stretch by 3.5 cm.