Answer:
upwards
downwards
Explanation:
Given:
weight of the person, 
So, the mass of the person:



- Now if the apparent weight in the elevator,

<u>Then the difference between the two weights is :</u>


is the force that acts on the body which generates the acceleration.
Now the corresponding acceleration:


upwards, because the normal reaction that due to the weight of the body is increased here.
- Now if the apparent weight in the elevator,

<u>Then the difference between the two weights is :</u>


is the force that acts on the body which generates the acceleration.
Now the corresponding acceleration:


downwards, because the normal reaction that due to the weight of the body is decreased here.
A = 1.15m/s2, Vf = 80.0km/h --> we need it in m/s, so:
Vf = 80km/h × 1000m/1km × 1h/3600s
= 22.22m/s
Top speed = Vf, initial speed = Vi
time (t) = V(Vf-Vi) ÷ a
t = (22.22-0)m/s ÷ 1.15m/s2
t = 22.22m/s × s2/1.15m
= 19.32 seconds
Explanation:
potential energy = mass × gravity force × height
=20 × 10 × 25
= 5000 joules
A water pipe freezes and cracks on a cold night. <em> (D)</em>
There are three physical changes going on in this scenario:
1). The air gets cold and dark at night.
2). The water in the pipe freezes and expands.
3). The pipe cracks.
There are no chemical changes in the description.