An object is moving with constant velocity downwards on a frictionless inclined plane that makes an angle of θ with the horizontal.
1. Which direction does the force of gravity act on the object?
2. Which direction does the normal force act on the object?
Which force is responsible for the object moving down the incline?
Answer:
The answer is below
Explanation:
1. When an object is moving with a constant velocity, the direction the force of gravity act on the object is DIRECTLY DOWN.
2. When an object is moving with a constant velocity, the direction the normal force act on the object "perpendicular to the surface of the plane."
3. When an object is moving with a constant velocity, the force that is responsible for the object moving down the incline is "the component of the gravitational force parallel to the surface of the inclined plane."
Answer:
The maximum velocity the mass can have if the string is not to break = 29.05 m/s
Explanation:
The force balance in the mass:
The tension in the string must always be equal to the force keeping the mass in horizontal circular motion.
The force keeping the mass in circular motion is given by
F = mv²/r
m = mass of body = 0.4 kg
v = speed of the body in circular motion
r = radius of the circular motion = 0.75 m
Maximum tension the string can withstand will correspond to the maximum velocity of the body in horizontal circular motion
T = F = mv²/r
450 = (0.4)(v²)/(0.75)
v² = 450×0.75/0.4 = 843.75
v = 29.05 m/s
Answer:
560 m
Explanation:
The speed of sound in air is approximately:
v ≈ v₀ + 0.6T
where v₀ is the speed of sound at 0°C (273 K) in m/s, and T is the temperature in Celsius.
The speed of sound at 20°C at that altitude is:
v ≈ 327 + 0.6(20)
v ≈ 339 m/s
The sound travels from the hikers to the mountain and back again, so it travels twice the distance.
339 m/s = 2d / 3.3 s
2d = 1118.7 m
d = 559.35 m
Rounding, the mountain is approximately 560 m away.
Answer:
The answer is 
Explanation:
The amount of energy is not enough to apply the relativistic formula of energy 
, so the definition of energy in this case is
.
From the last equation,
where
and the mass of the neutron is
.
Then
the equivalent of 
the speed of light.
Answer:
a) 0 J
b) W = nRTln(Vf/Vi)
c) ΔQ = nRTln(Vf/Vi)
d) ΔQ = W
Explanation:
a) To find the change in the internal energy you use the 1st law of thermodynamics:
Q: heat transfer
W: work done by the gas
The gas is compressed isothermally, then, there is no change in the internal energy and you have
ΔU = 0 J
b) The work is done by the gas, not over the gas.
The work is given by the following formula:
n: moles
R: ideal gas constant
T: constant temperature
Vf: final volume
Vi: initial volume
Vf < Vi, then W < 0 and the work is done on the gas
c) The gas has been compressed. Thus, its temperature increases and heat has been transferred to the gas.
The amount of heat is equal to the work done W
d)
