<span>Step 1 -- determine the acceleration of the 200-g block after bullet hits it
a = (coeff of friction) * g
g = acceleration due to gravity = 9.8 m/sec^2 (constant)
a = 0.400*9.8
a = 3.92 m/sec^2
Step 2 -- determine the speed of the block after the bullet hits it
Vf^2 - Vb^2 = 2(a)(s)
where
Vf = final velocity = 0 (since it will stop)
Vb = velocity of block after bullet hits it
a = -3.92 m/sec^2
s = stopping distance = 8 m (given)
Substituting values,
0 - Vb^2 = 2(-3.92)(8)
Vb^2 = 62.72
Vb = 7.92 m/sec.
M1V1 + M2V2 = (M1 + M2)Vb
where
M1 = mass of the bullet = 10 g (given) = 0.010 kg.
V1 = velocity of bullet before impact
M2 = mass of block = 200 g (given) = 0.2 kg.
V2 = initial velocity of block = 0
Vb = 7.92 m/sec
Substituting values,
0.010(V1) + 0.2(0) = (0.010 + 0.2)(7.92)
Solving for V1,
V1 = 166.32 m/sec.
Therefore the answer is (B) 166 m/s!</span>
Answer:
C
Explanation:
Radiation affects both cancer cells and healthy cells, but it affects cancer cells more.
A car A house A phone they all can be renewable
We are given that the system “releases” heat of 2,500 J,
and that it “does work on the surroundings” by 7,655 J.
The highlighted words releases and does work on the surroundings
all refers to that it is the system itself which expends energy to do those
things. Therefore the action of releasing heat and doing work has both magnitudes
of negative value. Therefore:
heat released = - 2, 500 J
work done = - 7, 655 J
Which means that the total internal energy change of the
system is:
change in internal energy = heat released + work
<span>change in internal energy = - 2, 500 J + - 7, 655 J</span>
<span>change in internal energy = -10,155 J</span>
Answer:
The correct answer is option '5': The type of metal from which the plate is made.
Explanation:
According to the principle of photoelectric effect we know that electron's are only emitted from a surface of metal if the frequency of the light is larger than a threshold frequency that depends on the metal and is known as threshold function of the metal. The ejection of the electrons is independent of intensity of the incident light meaning any light of frequency lower than work function will not eject electrons from the metal no matter whatever the intensity of the light, or the surface area or thermal conductivity, time of illumination.
