Answer: The torque required is 0.0471 N m.
Explanation:
Mass of the disc = 200 g = 0.2 kg (1 kg =1000 g)
Radius of the disc == 10 cm = 0.1 m(1 m = 100 cm)
Angular acceleration =
Moment of inertia =
The torque required is 0.0471 N m.
A helicopter lifts a 72 kg astronaut 15 m vertically from the ocean by means of a cable. The acceleration of the astronaut is g/
1 answer:
Answer:
(a) 1058.4 J
(b) -10584 J
Explanation:
Parameters given:
Mass of astronaut, m = 72 kg
Distance moved by astronaut, d = 15 m
(a) WORK DONE BY FORCE FROM THE HELICOPTER
Work done is given as the product of Force applied to a body and the distance moved by the body:
W = F * d
The force from the helicopter is given as:
F = m * a
where a = acceleration of the astronaut due to the helicopter
Therefore, the work done is given as:
W = m * a * d
W = 72 * g/10 * 15
W =
W = 1058.4 J
(b) WORK DONE BY FORCE OF GRAVITY
W = F * d
The force of gravity is given as:
F = -m * g
where g = acceleration due to gravity
The negative sign is due to the fact that the astronaut moves in an opposite direction (upwards) to the force of gravity (Gravity acts downwards)
Therefore, the work done is given as:
W = -m * g * d
W = -72 * 9.8 * 15
W = -10584 J
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8.6 cm
Explanation:
Step 1:
In this we have to find the focal length of converging lens.
To find focal length we have,
where u = Object distance
v= Image distance
f = Focal length
Step 2:
(1/f) = 0.116
f = 1/0.116
f = 8.6 cm
8) The height of the shelf is 2.04 m
9) The gravitational potential energy is 100 J
Explanation:
8)
The gravitational potential energy of an object is given by:
where
m is the mass of the object
g is the acceleration of gravity
h is the heigth of the object, relative to the ground
For the object in this problem, we have
m = 10 kg
And we know that
PE = 200 J
Therefore we can re-arrange the formula to solve for h, the heigth of the object:
9)
As before, the gravitational potential energy of the object is given by:
where in this case, we have:
m = 10 kg is the mass of the object
h = 2.04 m is the height of the object from the ground
While in this case, the acceleration of gravity on this planet is
Substituting,
Learn more about potential energy:
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