When you put ice in the freezer, the water expands when in gets cold.
the sidewalks have cracks in them to make room for the expansion and contraction when it heats up and cools down.
as you drive a car, the heat from combustion causes metal to expand. when you turn the car off, the metal cools down and contracts

3 0

3 years ago

18. For every action, there is an equal and opposite reaction.

Andrews [41]

Answer:

Thats the third law______

3 0

4 years ago

Erickson’s psychosocial stages emphasize

Musya8 [376]

This question is true because it just is

4 0

3 years ago

A lead ball is dropped into a lake from a diving board 5.0 meters above the water. After entering the water, it sinks to the bot

xxMikexx [17]

Answer:

28.8 meters

Explanation:

We must first determine at which velocity the ball hits the water. To do so we will:

1) Assume no air resistance.

2) Use the Law of conservation of mechanical energy: E=K+P

Where

E is the mechanical energy (which is constant)

K is the kinetic energy.

P is the potential energy.

With this we have $\frac{m}{2} *v^{2} = m*g*h$

Where:

m is the balls's mass <- we will see that it cancels out and as such we don't need to know it.

v is the speed when it hits the water.

g is the gravitational constant (we will assume g=9.8 $\frac{m}{s^{2} }$ .

h is the height from which the ball fell.

Because when we initially drop the ball, all its energy is potential (and $P = - m*g*h$ ) and when it hits the water, all its energy is kinetic ( $K=\frac{m}{2} *v^{2}$ . And all that potential was converted to kinetic energy.

Now, from $\frac{m}{2} *v^{2} = m*g*h$ we can deduce that $v=\sqrt{2*g*h}$

Therefore v=9.6 $\frac{m}{s}$

Now, to answer how deep is the lake we just need to multiply that speed by the time it took the ball to reach the bottom.

So D=9.6 $\frac{m}{s}$ *3 $s$ =28.8 $m$

Which is our answer.

7 0

3 years ago

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