Answer:
Choices A, B, and C are correct.
Explanation:
Let us look at each of the choices one by one:
A. It is a vector
Yes. Velocity is a vector, or it's a speed with direction.
B. It is the change in displacement divided by the change in time.
Yes. The velocity can be written as
where 
is the displacement—a vector quantity.
C. It can be measured in meters per second.
Yes. The units of velocity are m/s, but also with a unit vector indicating the direction.
D. It is the slope of the acceleration vs. time graph.
Nope. The velocity is the slope of displacement vs. time graph.
Hence, only choices A, B, and C are correct.
Answer:
33 g.
Explanation:
Assuming no heat transfer can be possible except for heat exchange between water and steel, we can say that the heat lost by the knife, must be equal to the heat gained by the water.
As we have a limit for the maximum temperature of both elements (once reached a final thermal equilibrium), of 100ºC, which means that the maximum allowable change in temperature will be of 300º C for the knife, and of 80º C for the water.
Empirically , it has been showed that for a heat exchange process using only conduction, the heat needed to raise the temperature of a body, is proportional to the mass, being the proportionality constant a factor that depends on the material, called specific heat.
So, we can write the following equation:
cs*mk*Δtk = cw*mw*Δtw
Replacing by the givens of the question, we have:
0.11 cal/gºC * 80 g * 300ºC = 1 cal/gºC*mw*80ºC
Solving for mw = 2,640 cal / 80 cal/g =33 g.
a. The speed of the pendulum when it reaches the bottom is 0.9 m/s.
b. The height reached by the pendulum is 0.038 m.
c. When the pendulum no longer swing at all, all the kinetic energy of the pendulum has been used to overcome frictional force.
<h3>Kinetic energy of the pendulum when it reaches bottom</h3>
K.E = 100%P.E - 18%P.E
where;
K.E(bottom) = 0.82P.E
K.E(bottom) = 0.82(mgh)
K.E(bottom) = 0.82(1 x 9.8 x 0.05) = 0.402 J
<h3>Speed of the pendulum</h3>
K.E = ¹/₂mv²
2K.E = mv²
v² = (2K.E)/m
v² = (2 x 0.402)/1
v² = 0.804
v = √0.804
v = 0.9 m/s
<h3>Final potential energy </h3>
P.E = 100%K.E - 7%K.E
P.E = 93%K.E
P.E = 0.93(0.402 J)
P.E = 0.374 J
<h3>Height reached by the pendulum</h3>
P.E = mgh
h = P.E/mg
h = (0.374)/(1 x 9.8)
h = 0.038 m
<h3>when the pendulum stops</h3>
When the pendulum no longer swing at all, all the kinetic energy of the pendulum has been used to overcome frictional force.
Thus, the speed of the pendulum when it reaches the bottom is 0.9 m/s.
The height reached by the pendulum is 0.038 m.
When the pendulum no longer swing at all, all the kinetic energy of the pendulum has been used to overcome frictional force.
Learn more about pendulum here: brainly.com/question/26449711
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Acceleration = change in velocity/change in time
= (30 - 20) / 10 - 0
= 10 / 10
Acceleration = 1 m/s²
