She can put chalk in vinegar as the vinegar will disintegrate the chalk chemically demonstrating chemical changes. But for physical changes she can break the chalk into small pieces by smashing it with something or her hand.
elasticity stretches and can also return to it's normal size ..
Explanation:
The given data is as follows.
Angular velocity (
) = 2.23 rps
Distance from the center (R) = 0.379 m
First, we will convert revolutions per second into radian per second as follows.
= 2.23 revolutions per second
=
= 14.01 rad/s
Now, tangential speed will be calculated as follows.
Tangential speed, v =
= 0.379 x 14.01
= 5.31 m/s
Thus, we can conclude that the tack's tangential speed is 5.31 m/s.
Answer:
5.791244495 KNm
Explanation:
The height h is given by,
Potential energy, PE is given by
PE=mgh where m is mass of the woman, g is acceleration due to gravity whose value is taken as
and h is already given hence substituting 77 Kg for m we obtain
PE=21.6567095 KNm
We also know that Kinetic energy is given by
where v is the velocity and substituting v for 20.3 we obtain
KE=15.865465 KNm
Friction work is the difference between PE and KE hence
Friction work=21.6567095 KNm-15865.465 Nm=5.791244495 KNm