Question

1) If a person holds 50 kg object at a height of 2 m above the floor for 10 s. How much work is done? W = F×d

(2) The work done in lifting 30kg of bricks to a height of 20m is W = m ×g × d (Formula, W = F × d but Force = m × g)

(3) A total of 4900 J is used to lift a 50-kg mass. The mass is raised to a height (distance) of W = F ×d Formula W = m × g × d Formula

(4) A total of 490 J of work is needed to lift a body of unknown mass through a height of 10m. What is its mass? W = m × g × h Formula

(5) A 40-kg boy runs up a flight of stairs 4 m high in 4s. His power output is P = W/t Formula, Power = work/time, work = Force × distance P = m×g×h t

(6) A 1-kg object has kinetic energy of 1 J when its speed (velocity) is KE = 1/2 × m × v2

(7) A 1-kg object has potential energy of 1 J relative to the ground when it is at a height of PE = m × g × h (g = 9.8 m/s2)

(8) A weightlifter raises a 70-kg barbell from the floor to a height of 2.2 m in 1.2 s. What was his average power output during the lift? P = (W)/(t) Formula, Power = work/time, work = Force × distance Force = mass × gravity P = (m × g × h) /(t) (use this) (g = 9.8 m/s2)

Answer #1

1 a) Starting from rest, a 50 Kg person dives
into water from a height of 80 m above the water
surface. Air resistance is negligible. (Use g= 10 m/s2)
Calculate (A) the diver’s KE just before striking the water surface
(B) the velocity of the diver just before striking the water (C)
the work done by gravitational force on the diver (D) the power
delivered by gravitational force on the diver
b) A ball of mass m=0.2 Kg
sitting...

1.
A 2 kg ball drops from a height of 0.5 m to the table.
What will be the kinetic energy of the ball just before it hits the
table? (assume g= 9.8 m/s2)
Group of answer choices
9.8 J
49.0 J
20.1 J
124 J
24.5 J
2.
Convert the velocity of 100 miles per hour into meters
per second using 1 mile = 1600 meter, and 1 hour = 3600
seconds
Group of answer choices
99.9 m/s
44.4...

1)A object is released from rest from a height of 1.8 m and
moves down the incline as shown. What is the angular speed of the
object when it reaches the horizontal surface? (ignore the
rotational kinetic energy, friction force, drag force).The mass of
the object is 50.0 kg. a)5.9 m/s b)3.3 m/s c) 2.5 m/s d)1.8 m/s
2) a 5.0 kg bird, accelerating from rest at a constant rate,
experiences a displacement of 28 m in 11 seconds. What...

1) A force of 210 N is needed to push a table across a level
classroom floor for a distance of 2.8 m. How much work was done on
the table?
2) Use g = 9.8 m/s2.
If 4,090 J of work is used to raise a 118 kg crate to a shelf in a
warehouse, how high was the crate raised?
3) Use g = 9.8 m/s2.
A 66.2 kg student runs up a 5.25 m high stairway in...

A
ball of mass 5.93 kg is released from rest at height 7.62 m above
the floor. It falls, hits the ground, and rebounds to height 3.2 m
above the floor. Assume none of the losses are due to air friction.
Find the work done against friction, in J, on the ball during the
contact with the ground

A luge and its rider, with a total mass of 50 kg, emerge from a
downhill track onto a horizontal straight track with an initial
speed of 39 m/s. If a force slows them to a stop at a constant rate
of 1.2 m/s2, (a) what magnitude
F is required for the force, (b) what
distance d do they travel while slowing, and
(c) what work W is done on them by the
force? What are (d) F,
(e) d,...

An object of mass m = 20.0 kg travels distance
d = 60.0 m at constant speed on a rough horizontal surface
(μk = 0.45). The force (a pull, not a push)
applied to the object makes an angle θ = 30.0∘with the
horizontal. Calculate:
A:The magnitude of the applied force?
B:The work done by the applied force?
C:The work done by the force of friction?

A 350 kg crate is being LOWERED by a person a distance 10 m
with a force (FP) of 80
N(the person is pulling upward but the crate is moving
downward). The rough ramp
exerts a constant force of friction of 70 N. The angle that
the ramp makes with the
0 floor is 30 .
(a) Draw a free body diagram for the crate.
(b) What is the work done by the person on the crate?
(c) What is...

As shown in the figure below, a box of mass
m = 64.0 kg
(initially at rest) is pushed a distance
d = 80.0 m
across a rough warehouse floor by an applied force of
FA = 222 N
directed at an angle of 30.0° below the horizontal. The
coefficient of kinetic friction between the floor and the box is
0.100. Determine the following. (For parts (a) through (d), give
your answer to the nearest multiple of 10.)
(a)
work...

An object of mass 5 kg is released from rest 24525 m above the
ground and allowed to fall under the influence of gravity. Assume
the gravitational force is constant, with g=9.8 m/sec2 , and the
force due to air resistance is proportional to the velocity of the
object with proportionality constant k= 1 kg/sec. Approximate when
(in seconds) the object will strike the ground.

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