Physics Midterm
When velocity is positive and acceleration is negative, what happens to the object's motion?
the object slows down
The statement by Newton that "an object in motion tends to remain in motion" is regarded to which of his laws of motion?
first
Acceleration due to gravity is also called
free - fall acceleration
Of the known 8 planets in the solar system, the innermost one, Mercury has which of the following?
greatest centripetal acceleration
Mass, along with what other two quantities, make up the three basic quantities in International System used by physicist to derive additional quantities?
length and time
Which of the following units are used to measure acceleration during free fall?
m/s^2
The reason the moon does not crash onto the earth is that the:
moon has a enough tangential speed
An artificial earth satellite in an elliptical orbit has its greatest speed when it is at what location?
nearest the Earth
Consider a point on a bicycle tire, as the wheel makes exactly four complete revolutions about a fixed axis. Compare the linear and angular displacement of the point.
only the linear displacement is zero
A body on earth has inertia, mass, and weight. Which of these properties change(s) when the body is taken to another planet?
only weight
Which of the following energy forms is associated with an object due to its position?
potential energy
Which of the following is the rate at which energy transferred?
power
Work is done when
the displacement is not zero
Which would hit the ground fist if dropped from the same height in a vacuum, a feather or a metal bolt?
they would hit the ground at the same time
If the displacement of an object, x, is related to velocity, v, according to the relationship x=Av, the constant, A, has the dimension of which of the following?
time
Of the following, which type of quantity is characterized by both magnitude and direction?
vector
A car goes forward along a level road at constant velocity. The total force acting on the tires is?
zero
What is the area of a football field (160ftX300ft) in square meters?
4,459.35 m2
On planet Pack, the standard unit of length is the "nose". If a 6.1 foot tall astronaut travels to that planet and is measured to have a height of 94 noses, what would be the height in feet of his partner who measures 76 noses?
4.9 feet
A city jogger runs 10 blocks due east, five blocks due south and another 10 blocks due west. Assume all the blocks are equal size. What is the magnitude of the jogger's displacement, start to finish?
5 blocks
The acceleration due to gravity on the surface of planet Q is three times that on the Earth. Thus an object with a measured mass of 5.0 kg on Earth would have what mass on planet Q?
5 kg
On planet Zork the standard unit of volume is call the "aqua". Space travelers from earth have determined 1 liter = 38.2 aquas. If so, how many aquas are contained in 150 liters?
5,730
A soccer ball is kicked horizontally. What is its average speed if after 4.00 s its displacement is 21.0 m ?
5.25 m/s
One angle of a right triangle is 30 degrees and the opposite side to that angle is 4 m long. The lengths of the remaining sides are:
6.93m and 8m
In order to test the physiological effects of a large acceleration, a person is strapped 4.4 m away from the axis of the machine that rotates at 40 rpm. How many times the acceleration of gravity will the centripetal force be?
7.87
A 3 -lb block is placed on top of a 5-lb block that is in a stable position on a table. What is the magnitude of the force exerted by the table on the 5-lb block?
8 lb
A fireman, 50m away from a burning building, directs a stream of water from a fire hose at an angle of 300 above the horizontal. If the velocity of the stream is 40 m/s, at what height will the stream of water strike the building?
9.6 m
At the Olympics the 1500m race is sometimes called the "metric mile". How many miles is the race?
932 miles
A trucker drives with an average velocity of 27 m/s toward the east on a perfectly straight highway. What will the trucker's displacement be after 2.0 hours?
97km to the east
If the mass in a horizontal mass-spring system was doubled, the elastic potential energy in the system would be changed by a factor of?
0 (no change)
A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ice-cream cone?
0 J
What is the speed of an object at rest?
0.0 m/s
A point on the rim of a 5 cm radius rotating wheel has a centripetal acceleration of 4 m/s^2. What is the centripetal acceleration of a point 20 cm from the center of the same wheel?
1.0 m/s^2
A military helicopter has rotor blades 3 m long rotating at 600 rpm. What is the centripetal acceleration of the rotating blades?
11844 m/s^2
The acceleration due to gravity on the surface of planet Q is three times that on the Earth. Thus an object with a measured mass of 5.0 kg on Earth would have what weight on planet Q?
147 kg
A military helicopter has rotor blades 3 m long and are rotating at 600 rpm. What is the tangential velocity of each blade tip?
188 m/s
How much power is required to lift a 2.0 kg mass at a speed of 2.0 m/s?
2 W
An object of what mass acted upon by a net force of 20 N will experience an acceleration of 10 m/s^2?
2 kg
A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the 200 N force on the television set?
2000 J
Find the resultant of the following two vectors i) 200 units at 0o and ii) 400 units at 150 degress
248 units at 126 degrees
Ball A has triple the mass and speed of ball B. What is the ratio of the kinetic energy of ball A to ball B.
27
11. A hiker travels south along a straight path for 1.5 hours with an average velocity of 0.75km/h, then travels south for 2.5 hours with an average velocity of 0.90 km/h. What is the hiker's displacement for the total trip?
3.4 km to the south
A shopping cart is given an initial velocity of 2.0 m/s and experiences a constant acceleration of 3.0 m/s2. What is the magnitude of the cart's displacement after the first 4.0s of its motion?
32m
The distance by air from New York to Los Angeles is 2120 miles. How far is this distance in kilometers?
3427.17 km
For the astronauts inside the orbiting space shuttle, there is no force of earth's gravity acting on them. This statement is:
Always true while in orbit
The baseball catcher throws a ball vertically upward an catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity an nonzero acceleration at the same time?
At the top of its trajectory
Since 1967 the standard definition for a second of time has been based on which of the following?
Characteristic frequency of the Cesium-133 atom
Since 1983 the standard meter has been defined in terms of which of the following?
Distance that light travels in 3.33564095x10^-9 seconds
If a baseball has a negative velocity and a negative acceleration, the velocity will then
Increase
Why doesn't the principle of mechanical energy conservation hold in situations when frictional forces are present?
Kinetic energy is not completely converted to a form of potential energy.
What are the units for a spring constant?
N/m
Which would hit the ground first if dropped from the same height in a vacuum, a feather or a metal bolt?
They would it the ground at the same time
If the mass of the earth increased with no change in the radius, your weight would:
also increase
Which one subtracts a velocity vector from another velocity vector, the result is which of the following?
another velocity vector
Human reaction time is usually about 0.2 s. If your lab partner holds a ruler between your finger and thumb and releases it without warning, how far can you expect the ruler to fall before you catch it?(ignore air resistance)
at least 19.6 cm
The baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and nonzero acceleration at the same time?
at the top of its trajectory
If it is known that a net force is acting on an object, then which of the following must be assumed regarding the object's condition? The object is:
being accelerated
In addition to displacement, which of the following must be used for more complete description of the average velocity of an object?
change in time
If a baseball has a negative velocity and a negative acceleration, the velocity will then
decreases
In addition to displacement, which of the following must be used for more complete description of the average velocity of an object?
delta t