A stone falls from a ledge and takes 8 seconds to hit the ground. The stone has an original velocity of 0 m/s. How tall is the ledge?
A. 1,254.4 meters
B. 78.4 meters
C. 39.2 meters
D. 313.6

meters

y(8) = -1/2 (9.81 * 8 ) = 313.92 m
so is D. 313.6 meters

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The orbits of planets being elliptical was one the planetary laws developed by
A. Ptolemy.
B. Brahe.
C. Copernicus.
D. Kepler.
**Weegy:** The orbits of planets being elliptical was one the planetary laws developed by Kepler. **User:** In a practical machine, the power output is _______ the power input.
A. smaller than
B. larger than
C. multiplied by
D. equal to
**Weegy:** In a practical machine, the power output is smaller than the power input.
Source: **User:** According to Ptolemy's model of the movement of celestial bodies,
A. the sun is the center of the universe.
B. planets orbit in circular paths around the earth.
C. the earth rotates around the sun.
D. the earth rotates around the moon.
**Weegy:** According to Ptolemy's model of the movement of celestial bodies,: C. planets orbit in circular paths around the earth. **User:** An object has a mass of 120 kg on the moon. What is the force of gravity acting on the object on the moon?
A. 196 N
B. 1,176 N
C. 20 N
D. 12.24 N
**Weegy:** C. 196 N **User:** Oil flows upward in the wick of a lantern because of the liquid property called
A. density.
B. viscosity.
C. meniscusity.
D. capillarity.
**Weegy:** Oil flows upward in the wick of a lantern because of the liquid property called A. [ viscosity.
'When fluid is forced through a tube, the fluid generally moves faster near the axis and very slowly near the walls, therefore some stress is needed to overcome the friction between layers and keep the fluid moving. For the same velocity pattern, the stress required is proportional to the fluid's viscosity.' ] **User:** An object with a mass of 78 kilograms is lifted through a height of 6 meters. How much work is done?
A. 47.75 J
B. 764.4 J
C. 4,586.4 J
D. 468 J
**Weegy:** D. [ 4,586.4 J
use the formula W = mgs
W stands for work done in joules
m stands for mass of the object
g stands for gravity
s stands for the distance the object is lifted
W = mgs
W = 78kilograms 9.8m/s2 6meters
W = 4586.4 J (joules)
answer would be 4,586.4 J ] **User:** A tank with a flat bottom is filled with water to a height of 4 meters. What is the ... (More)

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Asked 1/5/2014 5:44:08 PM

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The ratio of output power to input power, in percent, is called
A. efficiency.
B. work.
C. conductivity.
D. horsepower.
**Weegy:** The ratio of output power to input power, in percent, is called: B. EFFICIENCY. **User:** A naturally occurring force related to two bodies in motion is _______ force.
A. centrifugal
B. gravitational
C. frictional
D. centripetal
**Weegy:** A naturally occurring force related to two bodies in motion is __ A. gravitational _____ force.
**User:** If the velocity of an object changes from 65 m/s to 98 m/s during a time interval of 12 s, what is the acceleration of the object?
A. 2.75 m/s
B. 13.58 m/s
C. 33 m/s
D. 5.42 m/s
**Weegy:** C. 2.75 is the acceleration of the object. SOLUTION: (98 m/s - 65 m/s) / 12s = 33 m/s / 12s = 2.75 m/s^2 **User:** In which of the following units is acceleration expressed?
A. Foot-pounds
B. Meters per second squared
C. Kilograms
D. Newtons **Weegy:** Acceleration is expressed in: A. meters per second squared. **User:** What is the kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s?
A. 6,000 J
B. 5,880 J
C. 2,940 J
D. 12,000 J
**Weegy:** Answer : C. The kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s is 6,000 J.
k.e.=1/2 mv^2
=1/2*30*(20)^2
=15*400
=6000 kg m^2/s^2
=6000J **User:** A center-seeking force related to acceleration is _______ force.
A. centripetal
B. frictional
C. gravitational
D. centrifugal
**Weegy:** A center-seeking force related to acceleration is centripetal force.
Source: hyperphysics.phy-astr.gsu.edu/hbase/cf.html **User:** A car with a mass of 1,200 kilograms is moving around a circular curve at a uniform velocity of 20 meters per second. The centripetal force on the car is 6,000 newtons. What is the radius of the curve?
A. 160 meters
B. 16 meters
C. 80 meters
D. 32 meters
**Weegy:** The answer is D. 80 meters **User:** The metric unit of force is the
A. kilogram.
B. gram.
C. newton.
D. nanometer.
**Weegy:** The metric unit of force is the newton. **User:** How much time should be allowed ... (More)

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Asked 1/5/2014 5:53:00 PM

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