Answer: 321 J
Explanation:
Given
Mass of the box 
Force applied is 
Displacement of the box is 
Velocity acquired by the box is 
acceleration associated with it is 
Work done by force is 
change in kinetic energy is 
According to work-energy theorem, work done by all the forces is equal to the change in the kinetic energy
![\Rightarrow W+W_f=\Delta K\quad [W_f=\text{Work done by friction}]\\\\\Rightarrow 375+W_f=54\\\Rightarrow W_f=-321\ J](https://tex.z-dn.net/?f=%5CRightarrow%20W%2BW_f%3D%5CDelta%20K%5Cquad%20%5BW_f%3D%5Ctext%7BWork%20done%20by%20friction%7D%5D%5C%5C%5C%5C%5CRightarrow%20375%2BW_f%3D54%5C%5C%5CRightarrow%20W_f%3D-321%5C%20J)
Therefore, the magnitude of work done by friction is 
The weight is the force experienced, whereas the mass represents the actual quantity of matter inside a body..
weigh on the surface of the earth is equal to mg
mass is m
and at the centre weight is 0 due to 0 acceleration that's 0 g
but mass is always constant and remains m, no matter where you are
Answer: because there is no displacement or movement in the watchman's work. according to science when displacement or movement take place it is said to be work. hope this helps you.
The acceleration is the correct answer
Chameleon's tongue is more fast than thought. Its long sticky tongue moves at an amazing ballistic speed which lashes out unsuspecting insects and bugs. Now let us see how fast it is.
GIven:
acceleration of the chameleon's tongue- 260 m/s
2 for 20 ms
constant speed 30 ms
50 ms total time
1/20 of a second
solution:
<u>260</u> = <u> n</u><u> </u>
20 50
<u>20 n </u>= <u>13, 000</u>
20 20
n= 650 m/s
