Answer:
what are the answers to select? or do you just say them
Explanation:
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Answer:
Air resistance slows down the ball
In space, there would be no air resistance
Explanation:
When an object moves through the air, there is a force acting in the opposite direction to the motion of the ball: this force is called air resistance.
Air resistance is due to the friction between the molecules of air and the molecules at the surface of the object - because of this frictional force, the object is slows down in its motion and loses some energy (which is converted into thermal energy of the surrounding air).
There is also the force of gravity (downward) that acts on the ball: however, this force does not slows down the ball in its motion, instead it accelerates it towards the ground.
In space, however, there is no air and no gravity. This means that there are no forces acting on the ball: therefore, the ball will not be slowed down, and therefore will continue its motion forever, at constant velocity, according to Newton's first law:
<em>An object at rest (or in motion) will stay at rest (or in motion at constant velocity) when the net external force acting on it is zero</em>
Answer:
Vf = 210 [m/s]
Av = 105 [m/s]
y = 2205 [m]
Explanation:
To solve this problem we must use the following formula of kinematics.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (released from the rest)
g = gravity acceleration = 10 [m/s²]
t = time = 21 [s]
Vf = 0 + (10*21)
Vf = 210 [m/s]
Note: The positive sign for the gravity acceleration means that the object is falling in the same direction of the gravity acceleration (downwards)
The average speed is defined as the sum of the final speed plus the initial speed divided by two. (the initial velocity is zero)
Av = (210 + 0)/2
Av = 105 [m/s]
To calculate the distance we must use the following equation of kinematics
44100 = 20*y
y = 2205 [m]
Answer:
- Newton's first law applies. An object at rest will stay that way until a force is applied.
- Any amount of effort can be applied to any amount of mass (in the ideal case). The question is not sufficiently specific.
Explanation:
A force is required to move an object because the object will stay at rest until a force is applied.
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The effort required to lift or push two masses instead of one depends on the desired effect. For the same kinetic energy, no more effort is required. For the same momentum, half the effort is required for two masses. For the same velocity, double the effort is required.
B is true, however that is not a way in which conserving and recycling paper helps manage energy sources...
