In the absence of air resistance, a ball thrown vertically upward with a certain initial KE will return to its original level with the same KE. When air resistance is a factor affecting the ball, will it return to its original level with the same, less, or more KE? Does your answer contradict the law of energy conservation?

Q: A man of mass 60 kg runs up a flight of 30 steps in 40 s. If each step is 20 cm high, calculate his…

A: Step 1   ∙Mass of man m=60kg   ∙Flight 30 steps in 40sec.   ∙Each step is 20cm high.

Q: Using energy considerations and assuming negligible air resistance, show that a rock thrown from a…

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Q: how much more work will be required to stretch it an additional 4.0 cm?

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Q: Show that when a 3.0-kg book is lifted 2.0 m its increase in gravitational potential energy is 60 J.

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Q: When a jumbo jet slows and descends on approach to landing, there is a decrease in both its kinetic…

A: According to the law of conservation of energy, the energy cannot be created or destroyed, but it…

Q: Using energy considerations and assuming negligible air resistance, show that a rock thrown from a…

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Q: If the energy stored in the spring when it was stretched .25 m was used to launch a .1kg ball…

A: Given, m=0.1 kg x=0.25 m energy stored in the spring =12kx2 Where k is the spring constant and x is…

Q: If an automobile were to have a 100% efficient engine, transferring all of the fuel’s energy to…

A: The efficiency of automobile is 100 %. This means that the efficiency is 1.

Q: Find the work done by non conservative friction forces. Weight of the ball = 400 grams Initial…

A: Work done on a body is given by the net change in the energy of the body. Initial energy of the ball…

Q: what is the power of a crane that lifts it uniformly in a hurry to a height of 5 meters during 5…

A: The work done is calculated as, W=mghW=200×9.8×5W=9800 J

Q: What is the minimum work required to push a car with a mass of 1,500 kg car a distance 200 m upwards…

A: Given data: Mass of the car (m) = 1,500 kg Incline distance (d) = 200 m Incline angle θ= 20°…

Q: Show that the gravitational potential energy of a 1000-kg boulder raised 5 m above ground level is…

A: The given mass of the boulder is,

Q: m above

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Q: Show that 50 W of power is required to give a brick 100 J of PE in a time of 2 s.

A: Power = Work done /Time Work Done = Change in Potential Energy = 100 J

Q: While pushing her younger brother on a swing, Ivy exerted an average force of 56 N through a…

A: Given Data : The average force exerted by Ivy is given as F = 56 N. The distance covered by ivy…

Q: How many watts of power do you expend when you exert a force of 1 N that moves a book 2 m in a time…

A: The power exerted on the book can be given by

Q: The car weighing 1.0 × 10³ kg has an engine with a power of 80 kW. What is the biggest acceleration…

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Q: You are an athlete who masses 80 kg. When doing a pushup you lift a total of about 56 kg a distance…

A: The gravitational force is, F=mg Here, F is the force, m is the mass and g is the acceleration due…

Q: Which requires more work - lifting a 50-kg sack a vertical distance of 2m or lifting a 25-kg sack a…

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Q: Calculate the kinetic energies (in J) of the following. a 2,004.0 kg automobile moving at 140.0…

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Q: A ball of 0.1 kg is dropped from rest. When it falls through a distance of 2 m, the work done by the…

A: The expression for work done is, W=F×d                                    F=force,d=dispalcement…

Q: You watch your friend take off in a jet plane, and you comment on the kinetic energy she has…

A: Both are correct.Kinetic energy always depends on the frame of reference of the observer. Since you…

Q: Why is it tiring to push hard against a solid wall even if no work is done? A 75 kg firefighter…

A: Q 1) We get tired because we use our energy to contract the muscles. We try to push the wall using…

Q: A ball was launched upwards and vertically at a speed 3 m/s up to a height 4 m. What the work done…

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Q: If a 1300-kg car has been lifted so it has 19500 J of potential energy, it was lifted up O 150 m O…

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Q: Give 5 situations in which work is not done on it.

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Q: if you pull a wagon with a force of 200 Newton's and it takes you 20 seconds to pull it 10 meters of…

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Q: The driver of a passenger car puts the car to "rest" at the speed of 90 km/h, therefore, the car's…

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Q: A stone at rest is dropped from a height of 10 m. If the air resistance is negligible, use…

A: The expression from conservation of mechanical energy,

Q: A basketball of mass 0.0400 kg is dropped from a height of 5.00 m to the ground and bounces back to…

A: Given data: Mass of the basketball is, m = 0.0400 kg Height from which basketball is dropped on…

Q: Which requires more work: stretching a strong spring a certain distance or stretching a weak spring…

A: Work done is a product of the force applied and the displacement in the direction of force applied.

Q: Show that about 786 W of power is expended when a 500-N barbell is lifted 2.2 m above the floor in…

A: The expression for the power is,

Q: An apple hanging from a limb has potential energy because of its height. If it falls, what becomes…

A: From conservation of energy, just before hitting the ground, the potential energy will convert into…

Q: Which has more kinetic energy, a 0.0020-kg bullet traveling at 400 m/s or a (6.4 x 107 )-kg ocean…

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Q: A 50-kg platform diver hits the water below with a kinetic energy of 5000 Joules. The height…

A: Given:  mass, m = 50 kg  kinetic energy, K = 5000 J  g = 10 m/s/s

Q: Using energy considerations and assuming negligible air resistance, show that a rock thrown from a…

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Q: If an object has momentum, it must also have A. Potential energy B. Kinetic energy C. Work D. All of…

A: Introduction : Momentum is equal to product of mass and  Velocity Where as the body which has…

Q: Why does the force of gravity does no work on a car that rolls down a hill but no work when it rolls…

A: Actually there is a small mistake in the given question. The question is the force of gravity does…

Q: On a playground slide, a child has potential energy that decreases by 1000 J while her kinetic…

A: The dissipative force involved during sliding motion is the frictional force between the ground and…

Q: A high diver steps off a diving platform that is 10 meters above the water. If no air resistance is…

A: Given: height of platform h = 10 m diver steps off from the platform

Q: A 3.0 kg ball is lifted two meters upward in two seconds, and a 6.0 kg ball is lifted one meter…

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Q: If force and distance traveled are tripled, how does that affect work? Is it also tripled or 1/3?:(

A: We know that work depends on force and distance travelled in the direction of force i.e W = F× D…

Q: Does the kinetic energy of a car change more when it goes from 10 to 20km/h or when it goes from…

A: Calculating the change in kinetic energy for the given velocity ranges:

Q: Why does a bicyclist pick up speed on a downhill road even when he is not pedaling? Does this…

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Q: How much work does gravity do on a 0.150 kg ball falling from a height of 10 m? (Neglect air…

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