<span>a. The ball accelerates downward with a force of 80.5 N.
This is a rather badly worded question since the answer depends upon whether or not the impact with the gym ceiling was elastic or non-elastic. With an elastic collision, the ball will accelerate downward with it's original force plus the acceleration due to gravity. With a non-elastic collision (the energy in the ball being used to damage the ceiling of the gym), then the initial energy the ball has would be expended while causing damage to the gym ceiling and then the ball would accelerate downward solely due to the force of gravity. In either case, we need to take into consideration the force of gravity. So multiply the mass of the ball by the gravitational acceleration, giving
F = 0.25 kg * 9.8 m/s^2 = 2.45 kg*m/s^2 = 2.45 N
Since the initial force is 78.0 newtons, let's add them
78.0 N + 2.45 N = 80.45 N
and after rounding to 3 figures, gives 80.5 N
So we have a possible answer of 2.45N or 80.5N depending upon if the collision is elastic or not.
And unfortunately, both possible answers are available.
Since no mention of the ceiling being damaged is made in the question, and to be honest a 100% non-elastic collision is highly unlikely, I will assume the collision is elastic, so the answer is "a".</span>
Potential energy, is energy due to its position.
Given: Mass m = 40 Kg; Height h = 50 m
Required: Potential energy P.E = ?
Formula: P.E = mgh P.E = (40 Kg)(9.8 m/s²)(50 m)
P.E = 19,600 J
The sun is made mostly up of Hydrogen.
Answer : 2446 years.
Explanation :
Length of semi major axis is, 
According to Kepler's third law, square of time period of an orbit is directly proportional to the cube of the semi major axis.
i.e 
where G is gravitational constant
M is mass of sun, 
So, 
since, 
So, orbital period is approximately 2446 years.
Answer:
Total distance = 700 m
Displacement = 500 m
Explanation:
Notice that Jed travelled a total of 3 x 100 m = 300 m in the North direction, and 300 m + 100 m = 400 m in the East direction. Therefore the total distance he travelled is: 300 + 400 = 700 m.
But the actual displacement is given by the Pythagorean theorem as the hypotenuse of a right angle triangle of legs 300 m and 400 m:
displacement = 
