Explanation:
Work done is given by the product of force and displacement.
Case 1,
1. A boy lifts a 2-newton box 0.8 meters.
W = 2 N × 0.8 m = 1.6 J
2. A boy lifts a 5-newton box 0.8 meters.
W = 5 N × 0.8 m = 4 J
3. A boy lifts a 8-newton box 0.2 meters.
W = 8 N × 0.2 m = 1.6 J
4. A boy lifts a 10-newton box 0.2 meters.
W = 10 N × 0.2 m = 2 J
Out of the four options, in option (2) ''A boy lifts a 5-newton box 0.8 meters'', the work done is 4 J. Hence, the greatest work done is 4 J.
<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:
A yellow banana reflects only yellow light,
Explanation:
All matter is made up of subatomic particles that contain atoms. This is false statement.
Everything in the universe is made of matter, and so, everything in the universe is made of atoms. An atom itself is made up of three tiny kinds of particles called subatomic particles: <u>protons, neutrons, and electrons</u>.
All matter is made up of substances called elements, which have specific chemical and physical properties and cannot be broken down into other substances through ordinary chemical reactions.
Matter is anything which have mass and occupy some volume.
On earth, solid, liquid, and gas are the most common states of matter. Not only is water the most common substance on earth, but it is also the only substance that commonly appears as a solid, a liquid, and a gas within the normal range of earth's temperatures.
Learn more about matter here:- brainly.com/question/16982523
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Q = 4.6E-6 C
<span>E = 2.6 kV/mm = 2600 kV/m = 2600000 V/m </span>
<span>ε = 8.85E-12 F/m </span>
<span>E = Q/Aε </span>
<span>A = Q/Eε = 4.6E-6/(2600000*8.85E-12) = 0.2 m^2</span>
