Answer:
a. P.E = 3430Joules.
b. Workdone = 3430Nm
Explanation:
<u>Given the following data;</u>
Mass = 70kg
Distance = 5m
We know that acceleration due to gravity is equal to 9.8m/s²
To find the potential energy;
Potential energy = mgh
P.E = 70*9.8*5
<em>P.E = 3430J</em>
b. To find the workdone;
Workdone = force * distance
But force = mass * acceleration
Force = 70*9.8
Force = 686 Newton.
Workdone = 686 * 5
<em>Workdone = 3430Nm</em>
Newton’s second law gives us the relationship of force F,
mass m and acceleration a. The formula is given as:
<span>F = m a -->
1</span>
However we also know that the relationship of mass m,
density ρ, and volume V is:
<span>m = V ρ -->
2</span>
Therefore substituting equation 2 to equation 1:
F = ρ V a = ρ V g
where a is acceleration due to gravity, ρ is density of
water and V is the volume of the casting, therefore:
F = (1x10^-3 kg/cm^3) (4840 cm^3) (9.8 m/s^2)
F = 47.432 kg m/s^2
F = 47.432 N
Going back to equation 1:
47.432 N = m (9.8 m/s^2)
m = 4.84 kg
<span>Hence the weight of the final casting is 4.84 kg</span>
Answer:
Workdone = 20 Joules
Explanation:
Given the following data;
Force = 10N
Extension, e = 4cm to meters = 4/100 = 0.04 meters
Workdone extension = 40cm to meters = 40/100 = 0.4 meters
To find the work done;
First of all, we would find the spring constant using the formula;
Force = spring constant * extension
10 = spring constant * 0.04
Spring constant = 10/0.04
Spring constant = 250 N/m
Next, we find the work done;
Workdone = ½ke²
Where;
k is the spring constant.
e is the extension.
Substituting into the formula, we have;
Workdone = ½ * 250 * 0.4²
Workdone = 125 * 0.16
Workdone = 20 Joules
Explanation:
A or E I think cous I use to do this in yr 7
The magnitude of the electric force between two obejcts with charge
and
is given by Coulomb's law:
where
is the Coulomb's constant
and r is the distance between the two objects.
In our problem, the distance is
, while the magnitudes of the two charges are
(we can neglect the sign of the second charge, since we are interested only in the magnitude of the force).
So, using the formula and the data of the problem, we find
