<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>
Answer:
avg speed =total distance/total time
total distance =2km (given)
total time=1/10 +1/25=7/50
so avg speed =100/7=14.28
Answer:
D (Not too sure)
Explanation:
Natural selection favors the species that can work the best in the environment.
Sum of the first ten digits is:
7+3+4+5+4+1+7+8+0 = 39
39, when divided by 9 give you the remainder of 3
9 x4, is 36
36 +3 equals 39
(39 = 9 x 4 + 3)
So X= 0
Answer:
When you put un-like poles together (South facing North) you can feel magnetic attraction. In the Northern Hemisphere, your compass needle points North, but if you think about it for a moment, you will discover that the magnetic pole in the Earth's Northern Hemisphere has to be a South polarity.
