Answer: Looked it up but
Explanation:
When the skater lands on the track, the vertical component of his kinetic energy is converted to thermal energy. You can do experiments where there is no loss to thermal energy (only PE and KE conversions) by turning friction off and by making sure the skater doesn't leave the track.
Answer:
(a) 
(b) 
(c) 
Explanation:
(a) According to Newton's second law, the acceleration of a body is directly proportional to the force exerted on it and inversely proportional to it's mass.

(b) According to Newton's third law, the force that the sled exerts on the girl is equal in magnitude but opposite in the direction of the force that the girl exerts on the sled:

(c) Using the kinematics equation:

For the girl, we have
and
. So:

For the sled, we have
. So:

When they meet, the final positions are the same. So, equaling (1) and (2) and solving for t:

Now, we solve (1) for 

Answer:
Try to chase it or try to put up missing posters if you cant him/her, i never had a dog but i would do that and ask neighbors if they know where the dog is at.
Explanation:
30 Grams would be your answer (I took the test and got it right)
The <em>mass</em> of an object is a measure of how much stuff it's made of. So it's
a property of the object, like the object's length or color. It doesn't depend on
where the object is located right now, or on what else is around it..
The <em>weight</em> of an object is the measure of the gravitational force between it
and something else. The strength of the force depends on the size of both
masses, and also on how far apart they are. So the weight does depend on
where the object is located right now, and on what else is around it.
I think that sums it up fairly well.