Answer:

Explanation:
<u>Motion With Constant Acceleration
</u>
It's a type of motion in which the velocity of an object changes uniformly in time.
The formula to calculate the change of velocities is:

Where:
a = acceleration
vo = initial speed
vf = final speed
t = time
The roller coaster moves from vo=6 m/s to vf=70 m/s in t=4 seconds. To calculate the acceleration, solve for a:



Same speed, because mass is neglected. The things that affect the speed are the distance and speed of the rock.
Answer:
K = 0.076 J
Explanation:
The height of the target, h = 0.860 m
The mass of the steel ball, m = 0.0120 kg
Distance moved, d = 1.50 m
We need to find the kinetic energy (in joules) of the target ball just after it is struck. Let t is the time taken by the ball to reach the ground.

Put all the values,

The velocity of the ball is :

The kinetic energy of the ball is :

So, the required kinetic energy is 0.076 J.
Answer:
Explanation:
The calcite Crystal can be identified by carrying out an acid test on it. This is done by bringing it in contact with a weak acid which cause crack in it structure. Hence a little of carbondioxide gas is released.
Since diamond is the hardest object,it can be identified on a Mohs scale. Likewise it can be tested by bringing it in contact with a newspaper, if the letters on the paper are not seen, that shows it is a pure diamond.
Window glass is identified by the code on it.
While Quartz Crystal is identified by scratch test. When it is used to scratch all other softer stones and metal, it leaves mark on them.