Answer: B
Explanation:
Newton's first law it's law of inertia.
An object at rest will remain at rest (or an object in motion in a straight line at a constant velocity will remain that way) unless it is acted by an unbalanced force.
In A for the ball to slow down and stop, an external force (like friction with air or the floor) needs to be taken in consideration.
In B we can see how we need to make a force on the wagon to make it move.
In C we have an other Newton 's law, force equals mass times acceleration (2nd law)
In D we can see how it does not move because the forces on the box are balanced.
Answer:Explanation:
A microscopic hair examination can also determine if a hair was forcibly removed, artificially treated or diseased. A comparison microscope can be used to compare a questioned hair to a known hair sample in order to determine if the hairs are similar and if they could have come from a common source.
Answer:
P=160000Pa
Explanation:
You haven't specified what to calculate
But looking at the parameters I think the question is asking to calculate the pressure exerted.
Pressure=Force/Area
P=40000/0.25m²
P=160000Pa
We can solve the problem by using the law of conservation of energy.
Initially, the rock has only gravitational potential energy, which is given by
where mg is the weigth of the rock (2200 N), while h is the height at which the rock has been released (h=15 m). If we calculate it, we get
Just before hitting the ground, the rock height is zero, so its potential energy is now zero. So the total mechanical energy of the rock now is just kinetic energy:
however, the mechanical energy of the rock must be conserved, so
and so we have that the kinetic energy of the rock just before hitting the ground is equal to its initial potential energy:
(A) -10m/s^2
(B) the average acceleration in the specified time in interval Δt = tb - ta =2.0sis
The rate at which the velocity changes is referred to as average acceleration. To determine the average acceleration of something, we divide the change in velocity by the amount of time that has passed.
For instance, the average acceleration of a crazy ball would be 20 cm/s/s if its velocity increased from 0 to 60 cm/s in 3 seconds. The marble's velocity will therefore rise by 20 cm/s per second as a result.
As a result, we can see that the definition of average acceleration is the ratio of change in velocity to change in time for a certain interval. The average acceleration is calculated over a given period of time and contrasted with instantaneous acceleration. The final velocity less the starting velocity divided by the total time is the average acceleration.
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