Classical Mechanics Answers

A

surface of the earth. When the satellite orbits around the earth at a height equal to the diameter of the earth (above the surface of the earth), the magnitude of the gravitational force on the satellite will be:

satellite experiences a gravitational force with magnitude F when it is on the

A 3F

B 2F

C 1/3 F

D 1/9 F

Consider the following statements with regard to Newton’s third law of motion:

I: The resultant of an action-reaction force pair is zero.

II: An object moves when the action force is larger than the reaction force.

III: The resultant of an action-reaction force pair cannot be determined, because

the force acts on different objects.

Which statement(s) above is/are correct?

A Only I

B Only II

C Only III

D Only II & III

A block with a mass of 0.20 kg is hung at the end of a spring and it is lifted vertically so that the spring is unstretched. The block is then realesed and it touches the table with a velocity of 0.80 m s-1. If the distance of the table from the realesed point of the spring is 0.10 m, what is the force constant of the spring?

Consider two steel balls. Ball 1 has a

weight of 1.5 N. Ball 2 has a weight

of 15 N. Both balls are released

simultaneously from a height of 2.0 m.

Which ball hits the ground first?

a) Ball 1 hits the ground first.

b) Ball 2 hits the ground first.

c) Both balls hit the ground at the

same time.

d) It can’t be determined from the

information provided.

I think that the answer will be (b) because the answer (c) will be right only if ignore the air resistance.

I got an answer before which is (c).

Why is that?

Thank you so much.

A two point system consists of two masses, m and 2m, separated by a distance d. If mass m is replaced by a mass 3m and is kept at a distance d/2, what are the ratios of the gravitational potential energy of the two systems?

A car has a drag coefficient C_{d} = 0.30

Cd

​=0.30, a frontal area of A=1.9 m

2

and a mass 1.2 tonnes. The density of air is 1.2 kg.m^{-3}

−3

.

i) What is the drag force when it is traveling at v=110 kph 

in a straight line? F_{drag} =

Fdrag

​= _____  N 

.

Hint: Retain accurate values until the final calculation, but remember significant figures.

A rubber band has mass m=0.30 g 

and a spring constant k=15 N.m

−1

. I stretch it by 5.0 cm 

(which in this case doubles its length). Assume the rubber band behaves as a Hooke's law spring. Assume that, when you launch the rubber band, all of the stored potential energy is converted into kinetic energy. How fast is it at the launch?

v =

v= _____  m.s

−1

.

I drag a mass m=21 kg 

in a straight line, along a horizontal surface, a distance D=23 m 

. I drag it at constant speed v=0.90 m.s in a straight line using a horizontal force. The coefficients of friction are \mu_{s} = 1.2 μs​=1.2 and μk ​=1.1. How much work do I do? W =

W= _____  J 

.

Is internally created unidirectional force possible? Look closely at what the pistons of a rotary plane engine are doing.

estimate the hall voltages generated in each case across a 5mm width of sample of thickness 1mm when a current 100mA is passed along it and the perpendicular field is given as 100mT