Work power and Energy- Advance Level

Work power and Energy- Advance Level

Dear Readers,

Dynamics is the branch of physics developed in classical mechanics concerned with the study of forces and their effects on motion. Isaac Newton was the first to formulate the fundamental physical laws that govern dynamics in classical non-relativistic physics, especially his second law of motion. .

Q1. A labour has to throw bricks near mistry 16 feet vertically above. He throws the bricks in such a manner that the brick reach the mistry with the velocity of 16 ft/sec. If the throws bricks such that bricks just reach the mistry, then the portion of the energy saved is

•   1/3
•  1/4
•  1/5
•  1/6

Solution
the portion of the energy saved is 1/5

Q2.A hammer of mass 2 kg falls vertically through 1 metre on the top of a nail of mass 100 gm and drives it a distance of 10 cm in the ground. The resistance of the ground is

•  3441/210 kg wt
•  4441/210 kg wt
•  5441/210 kg wt
•  None of these

Solution
The resistance of the ground is 4441/210 kg wt

Q3.  A bullet of mass m penetrates a thickness a of a plate of mass M at rest. If this plate is free to move, then the thickness to which the bullet will penetrate is

•  Ma/(m+M)
•  ma/(m+M)
•  Ma/(m-M)
•  None of these

Solution
the thickness to which the bullet will penetrate is Ma/(m+M)

Q4. A glass marble, whose mass is falls from a height of 2.5 m and rebounds to a height of 1.6 m. Then the average force between the marble and the floor, if the time during which they are in contact be one-tenth of a second, is

•  10.58 N
•  11.58 N
•  12.58 N
•  13.58 N

Solution
the time during which they are in contact be one-tenth of a second, is 13.58 N

Q5.A fire engine lifts 50 kg water up to 2 m height per minutes and throws it out with the velocity of 19.62 m/sec. The horse power of engine will be

•   0.12
•  0.24
•  0.36
•  0.48

Solution
 The horse power of engine will be 0.24