Answer:
a) 


b) 

c)

Explanation:
We have:
m: is the ball's mass = 1.5 kg
v₀: is the initial speed = 15 m/s
g: is the gravity acceleration = 9.81 m/s²
a) In the initial position we have:
h: is the height = 0
The potential energy is given by:

The kinetic energy is:

And the mechanical energies:

b) At 5 m above the initial position we have:
h = 5 m
The potential energy is:

Now, to find the kinetic energy we need to calculate the speed at 5 m:



And the mechanical energies:
c) At its maximum height:
: is the final speed = 0

Now, the potential, kinetic and mechanical energies are:

I hope it helps you!
Answer:
Work done, W = 5534.53 J
Explanation:
It is given that,
Force acting on the piano, F = 6157 N
It is pushed up a distance of 2.41 m friction less plank.
Let W is the work done in sliding the piano up the plank at a slow constant rate. It is given by :

Since,
(in vertical direction)

W = 5534.53 J
So, the work done in sliding the piano up the plank is 5534.53 J. Hence, this is the required solution.
The heat (energy) needed to raise the temperature of the water is given by

The wavelength of the radiation of the oven is

, so the energy of a single photon of this radiation is

So, the number of photons required to heat the water is the total energy absorbed by the water divided by the energy of a single photon:

photons
Answer:
F= 403429 kpa
Explanation:
Pressure is the product of force and area
Mathematically,
P=F*A -------where F is force and A is area.
A= 40 *0.1 = 4mm² -----convert to m²
A= 4e⁻⁶ m²
P= 4000000 pa
F= P/A = 4000000/4e⁻⁶
F= 403428793.493 pa
F= 403429 kpa
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