physics quiz 6

If a centripetal acceleration is experienced or measured it necessarily follows that a balanced force acts in the direction of the acceleration the instantaneous velocity vector is in the same direction as the measured acceleration a reactive centrifugal acceleration exists a centrifugal force acts in the direction of the acceleration an unbalanced force acts in the direction of the acceleration

an unbalanced force acts in the direction of the acceleration

If the hanging bronze object's mass increases and the hanger mass and radius are held constant, the period . . . increases decreases remains the same goes to zero stabilizes

increases

The tendency of an object to oppose a change in its state of relative rest or constant velocity and measured by its mass is called momentum acceleration centripetal force inertia centrifugal force

inertia

The natural unit of angular displacement defined as the angle subtended by an arc length equal to one radius is called the degree (which is 1/360 of a complete revolution) mil (which is 1/6400 of a complete revolution) minute of arc (1/60 of 1/360 of a complete revolution) radian second of arc (1/60 of 1/60 of 1/360 of a complete revolution)

radian

Uniform circular motion means the velocity of the revolving mass is constant magnitude of the velocity vector increases at a constant rate direction of the acceleration is constant rate of change of the velocity vector opposes the acceleration speed of the revolving mass is constant

speed of the revolving mass is constant

What did you derive experimentally by changing the radius of the hanging bronze mass? the mass of the object the centripetal force the radius the height of the indicator bracket the speed of the object

the centripetal force

If a centripetal acceleration is experienced or measured it necessarily follows that a balanced force acts in the direction of the acceleration the instantaneous velocity vector is in the same direction as the measured acceleration a reactive centrifugal acceleration exists a centrifugal force acts in the direction of the acceleration the direction of the acceleration is in the direction of the change in velocity vector

the direction of the acceleration is in the direction of the change in velocity vector

Given w = angular speed in rad/sec and R = radius of the circular path of an object moving in uniform circular motion with period T and frequency f. The linear speed v of the object is expressed as v = w/R v = 2*Pi*f v = R*w^2 v = R*w v = R/w

v = R*w

At what angular speed would the earth have to rotate in order for objects at the equator to have no weight. Assume the radius of the earth to be 6.40E03 kilometers. HINT: weight = mg; g = 9.81 m/s^2. 0.00124 rad/s 0.071 rad/s 6125 rad/s 0.0012 rad/s 1.53x10^-6 rad/s

0.00124 rad/s

Given w = 62.8 rad/s and R = 0.5 m for an object moving in uniform circular motion, what is the period of the motion in seconds?(Use pi = 3.14) 0.100 s 0.1 s 10 s 100 s 6.28 s

0.100 s

Given w = 62.8 rad/s and R = 0.5 m for an object moving in uniform circular motion. In hertz what is the frequency of the motion? (Use pi = 3.14) 1.0 Hz 10.0 Hz 20 Hz 6.2 Hz 6.28 Hz

10.0 Hz

A 0.500 kg mass is attached to the end of a 1.50 m cord . The ball is whirled in a horizontal circle with a radius equal to the length of the string. If the cord can withstand a maximum tension of 50.0 N, what is the maximum speed the ball can have before the cord breaks? 0.75 m/s 150. m/s 15 m/s 12.2 m/s 12.25 m/s

12.2 m/s

One complete revolution corresponds to 360 degrees which corresponds to ____________. A radian is equal to approximately ___________. Pi radians; 57.29 degrees 2*Pi radians; 57.29 degrees Pi/4 radians; 60 degrees Pi/2 radians; 60 degrees 2 radians; 30 degrees

2*Pi radians; 57.29 degrees

Given w = 62.8 rad/s and R = 0.50 m for an object moving in uniform circular motion with period T. In m/s what is the linear speed of the motion? 62 m/s 31 m/s 31.4 m/s 12.3 m/s 6.28 m/s

31 m/s

In m/s what is the linear speed of a point at the equator on the surface of the earth? Assume the radius of the earth to be 6.40x10^3 kilometers. HINT: the earth rotates 2*Pi radians in 24.0 hours OR one rotation per day OR 360 degrees in 24.0 hours. 707 m/s 0.465 m/s 465 m/s 585 m/s 465.4 m/s

465 m/s

A car of mass 2000.0 kg is traveling at a constant speed of 85 m/s in a curve with radius 15 m. What is the centripetal acceleration? 1.7x10^5 m/s^2 482 m/s^2 480 m/s^2 5.7 m/s^2 5.70 m/s^2

480 m/s^2

In rad/s what is the angular speed of the earth? Assume the radius of the earth to be 6.40x10^3 km and the period of the Earth's rotation to be 23.9 hours. 7.27x10^-5 rad/s 2.62x10^-1 rad/s 7.272x10^-5 rad/s 5.43x10^5 rad/s 465 rad/s

7.27x10^-5 rad/s

Given w = 62.8 rad/s and R = 0.50 m for a 0.50 kg object moving in uniform circular motion, what is the centripetal force causing the object to accelerate? 15.7 N 985 N 990 N 500 N 246 N

990 N

Why do you find the percent difference between the two centripetal force values and not the percent error? Both values were calculated, therefore neither one was an accepted value Because there was no error in the experiment There was such a big difference between the two values Both A and B Both B and C

Both values were calculated, therefore neither one was an accepted value

Given w = angular speed in rad/sec and R = radius of the circular path of an object moving in uniform circular motion with period T and frequency f. Which of the following is NOT an expression of centripetal force? F = mRw^2 F = (mv^2)/R F = (4PI^2)*(f^2)*R*m F = ((4Pi^2)*R*m)/T^2 F = m*2*Pi*w

F = m*2*Pi*w

"An object's velocity remains constant unless acted upon by a net external force" is a statement of Newton's ________________. Zeroth Law First Law Second Law Third Law Law of Universal Gravitation

First Law

How could the error in finding the period be reduced in the experiment? Decrease the number of rotations. Increase the number of rotations. Measurement of mass

Increase the number of rotations.

Centripetal force is directed radially inward for an object traveling in a circle. What is applying the centripetal force? Mass of the trolley times the angular velocity squared divided by radius Friction of trolley against the sides The tension in the string You are applying the force by holding the string The rotating object itself

The tension in the string

What is the main source of error for the experiment? Measuring the mass of the object. Timing the ten rotations. Adding mass to the hanger. Placing the object at the correct radius. In order to provide variable pressure

Timing the ten rotations.

What was the purpose of setting the indicator bracket to the height of the orange indicator? To know if the hanging bronze object is hanging vertically To see the angular velocity To correct the moment of interia of the system To increase the force on the hanging bronze object None of the above

To know if the hanging bronze object is hanging vertically

Why did we need the slope of the graphs? To solve for values we wish to compare to the theorectical value. To find the next radius for the object. To find the height of the spring bracket. To find the length of the spring. To find the period.

To solve for values we wish to compare to the theorectical value.

Should the speed of rotation be kept constant? No Yes You measured the radius to be at the end of the track so that is where the trolley needs to be All of the above A and B

Yes

Centripetal literally means ____________ while centrifugal is defined as ______________. inside of center; outside of center radially outward; radially inward center-fleeing; center-seeking center-seeking; center-fleeing eccentric (off-center); intrinsic

center-seeking; center-fleeing

What is the term used to describe a fictitious force that seems to be directed outward along the radius of a circle acting on the rotating object of interest in uniform circular motion if the observer is located in the system of reference that moves with the object? force of friction force of gravity reaction to centripetal force centripetal force centrifugal force

centrifugal force

A centripetal force of 318 N acts on mass m = 2 kg moving in uniform circular motion of radius R = 1 m with w = 12.6 rad/s. No useful work is done by the centripetal force because centripetal force is fictitious the centripetal force is balanced by centrifugal force centripetal force acts perpendicular to the instantaneous displacement of the revolving mass all of the work is dissipated to friction the tangential component of the centripetal force equals the radial component

centripetal force acts perpendicular to the instantaneous displacement of the revolving mass