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
We can find the average speed of the body by finding the total distance covered, and then dividing it by the total time of the motion.
The total distance covered is:
while the total time of the motion is
So, the average speed of the body is:
The kinetic energy of an object is given by
KE = 0.5mv²
where m is the mass and v is the velocity.
To calculate the change in kinetic energy...
Initial KE:
KEi = 0.5mVi²
where Vi is the initial velocity.
Final KE:
KEf = 0.5mVf²
where Vf is the final velocity.
ΔKE = KEf - KEi
ΔKE = 0.5mVi² - 0.5mVf²
ΔKE = 0.5m(Vf²-Vi²)
Given values:
m = 16kg
Vi = 25m/s
Vf = 20m/s
Plug in the given values and solve for ΔKE:
ΔKE = 0.5×16×(20²-25²)
ΔKE = -1800J
8 meters per second. To find velocity is to divide distance by total time. so 400/50.
