Answer:
The acceleration of the object is 20 meters per second square = 20 m/s^2
Explanation:
Recall that acceleration is defined as the change in velocity divided the time it takes for the change. Therefore , if the object accelerates from rest (zero velocity) to 70 m/s , the change in velocity is (70 m/s - 0 m/s = 70 m/s)
which divided by the 3.5 seconds it took for the change, gives:
acceleration = (70 m/s / 3.5 s ) = 20 m/s^2
The added weight of the sand puts more downward pressure on the wheels contacting the rails, which would cause the trains speed to decrease.
Answer:
The S.I unit of heat is Joule .
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Explanation:
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Answer:
A) Its density will decrease
Explanation:
When an object is heated, its volume increases. This is due to the fact that the particles in the medium vibrate more (if it is a solid) or they move more (if it is a liquid or a gas), therefore they tend to occupy a larger space.
At the same time, the mass of the object does not change, because the mass just represents the amount of matter contained in the object, so it does not increase/decrease at different temperatures.
The density of an object is defined as the ratio between the mass (m) and the volume (V):

We said that the mass remains unchanged while the volume increases: since the density is inversely proportional to the volume, this means that the density decreases.