Explanation:
chemical changes
>produce new substances w/ different chemical structure/ properties
> thermal energy can be used to BREAK bonds (endothermic)
>thermal energy can be transferred to a chem rxn to help form new products (endothermic)
> heat can be released by an exothermic chemical reaction (excess energy- the total energy used to break bonds is less than energy released in forming new bonds)
physical changes
>does not result in new substances (typically changes in state- solid, liquid, gas)
> thermal energy can be transferred to EVAPORATE water (add thermal E... water (liquid) to steam (gas)) or FREEZE water (remove thermal E... water (liquid) to ice (solid))
The answer would be Gravity.
Gravity is pulling the weight down, which is pulling the car up the ramp.
Answer:
Work done on an object is equal to
FDcos(angle).
So, naturally, if you lift a book from the floor on top of the table you do work on it since you are applying a force through a distance.
However, I often see the example of carrying a book through a horizontal distance is not work. The reasoning given is this: The force you apply is in the vertical distance, countering gravity and thus not in the direction of motion.
But surely you must be applying a force (and thus work) in the horizontal direction as the book would stop due to air friction if not for your fingers?
Is applying a force through a distance only work if causes an acceleration? That wouldn't make sense in my mind. If you are dragging a sled through snow, you are still doing work on it, since the force is in the direction of motion. This goes even if velocity is constant due to friction.
Explanation:
Answer:
0.8 seconds
Explanation:
F=ma
Let x be the seconds the force is applied.
m = 20kg
F = 50 Newtons (kg*m/sec^2)
acceleration, a, is provided for x seconds to increase the speed from 1 m/s to 3 m/s, an increase of 2m/s
Let's calculate the acceleration of the cart:
F=ma
(50 kg*m/s^2) = (20kg)*a
a = 2.5 m/s^2
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The acceleration is 2.5 m/s^2. The cart increases speed by 2.5 m/s every second.
We want the number of seconds it takes to add 2.0 m/sec to the speed:
(2.5 m/s^2)*x = 2.0 m/s
x = (2.0/2.5) sec
x = 0.8 seconds
Mira is much bigger than the Sun.
Only very massive stars will go through a supernova stage, causing the outer layer to explode away and the core to collapse in on itself, becoming very dense.
