Physics Exam
It takes a 615 kg car 14.3 s to travel at a uniform speed around a circular racetrack 50.0 m radius. What is the acceleration of the car, and what is the force exerted by the track on the car's tires to produce this acceleration?
(a) 9.65 m/s^2 (b) 5.94 x 10^3 N
A stone is thrown horizontally from the top of a 25.00-m cliff. The stone lands at a distance of 40.00 m from the edge of the cliff. What is the initial horizontal velocity of the stone?
17.70 m/s
Three bugs that are connected by a mass less spider silk are pulled along a frictionless table top. The first bug has a mass of 1.5 g, the second, 2.0 g, and the third, .75 g. The spider pulling them exerts a force of 0.011 N. What is the acceleration of each bug?
2.6 m/s^2
A racehorse is running with a uniform speed of 69 km/hr along a straightaway. What is the time it takes for the horse to cover 400 meters?
21 seconds
What is the normal force acting on a 30.0 kg box measuring 1 m on a side that is moving across the ground horizontally at a velocity of 20.0 m/s? The coefficient of kinetic friction for wood on gravel is 0.45.
294 N
A runner moving at a speed of 8.8 m/s rounds a bend with a radius of 25 m. What is the runner's centripetal acceleration?
3.1 m/s^2
Little Georgie Atwood was playing with his blocks and some massless string. He connected the first block with mass M1 on one end of the string, put the string over a frictionless pulley, and attached the other block with mass M2 on the other end of the string. I M1=25.0 g and M2=55.0 g, what is the acceleration of each block?
3.68 m/s^2
The force of friction depends on the amount of surface area in contact between the two surfaces
false
Gravity is what type of force
field force
The rate at which an object's velocity changes is called its
acceleration
A planet moving in an elliptical orbit moves
both c and d c) slower when it is farther away from the sun d) faster when it is closer to the sun
In a free body diagram, the force arrows always point
both toward and away from the particle
The final position of the initial position is the
displacement
Acceleration can never be negative
false
What is the gravitational field of a bowling ball that has a mass of 7200 g and is 21.6 cm across?
4.12 x 10^-12
The coefficient of kinetic friction is NOT
more than the coefficient of static friction
A 50.0 kg wooden box is pushed across a floor with a constant speed of 2.5 m/s. The coefficient of kinetic friction is 0.20. If the force being applied to the box is halved, what is the resulting acceleration on the box?
-0.98 m/s^2
A car of mass 1330 kg is traveling at 28.0 m/s. The driver applies the brakes to bring the car to rest over a distance of 79.0 m. Calculate the retarding force acting on the car.
-6600 N
A sled dog pulls a loaded sled with a mass of 35 kg along a horizontal snow field at a constant speed. The coefficient of kinetic friction between the sled runners and the snow is 0.11 and the angle of the traces between the sled and the dog is 20 degrees.
...
Anissa rides her snowboard down a hill sloped at 25 degrees. The coefficient of kinetic friction between her and her skies is 0.15. If her mass is 55 kg, how fast is she 7 seconds after starting from rest?
...
Rafael is driving his car at 29 m/s. What is the shortest distance in which he can brake and stop if the coefficient of static friction between the tires and the road is 0.6?
...
The men pull a 31 kg box with forces 9.7 N and 7.6 N in the directions shown below. Find the resultant acceleration of the box and the direction in which the box moves.
0.07 m/s^2
You need to move a 53 kg armoire across the room. If you push with a force of 68 N, and the armoire accelerates at 0.10 m/s^2, what is the coefficient of friction on the carpet?
0.13 N
If a drag racer wins the final round of her race by going an average speed of 198.37 miles per hour in 4.537 seconds, what distance did he cover?
0.2500 miles
A 2.7 -kg box is released on a horizontal surface with an initial speed of 2.9 m/s.? It moves on the surface with a deceleration of 0.27 m/s^2. Calculate the kinetic friction force on the box.
0.73 N
Julia throws a ball vertically upward from the ground with a speed of 5.89 m/s
0.92 s
A ball is thrown vertically upward with a speed of 1.53 m/s from a point 4.21 m above the ground. Calculate the time in which the ball will reach the ground.
1.09 s
Jupiter orbits the sun with an orbital radius of 7.78 x 10^11 m. Given that the mass of the Sun is 2.00 x 10^30 kg, calculate the orbital velocity of Jupiter.
1.3 x 10^4 m/s
The orbital period for Saturn is 10,832.327 days. The average distance between Saturn and the Sun is 1,400,000,000 km. If G = 6.67 x 10^-11 N m2/kg2, estimate the mass of the Sun.
1.8 x 10^30 kg
A moose pushes a barrel with a mass of 6.8 kg for a distance of 8.5 m over the frictionless surface of a frozen pond. He exerts a constant 50 N force as he does so. If the final velocity is 15 m/s, what was the initial velocity?
10 m/s
A block with mass 4.4 kg is free to slide along a horizontal frictionless air hockey table. This sliding block is connected by a string and pulley to a second block with mass 2.9 kg that is hanging over the edge of the table. The hanging block will fall, pulling the sliding block to the right. Find the acceleration of the sliding block.
3.9 m/s^2
A 50.0 kg wooden box is pushed across a floor with a constant speed of 2.5 m/s. The coefficient of kinetic friction is 0.20. If the force being applied to the box is tripled, what is the resulting acceleration on the box?
3.92 m/s^2
A ball is thrown horizontally at 10.0 m/s from the top of a hill at 50.0 m high. How far from the base of the cliff would the ball hit the ground?
31.9 m
A missile launches at a velocity of 30.0 m/s at an angle of 30.0° to the normal. What is the maximum height the missile attains?
34.4 m
Two horizontal forces, 315N and 145N are applied to a sled resting on a frictionless skating rink. If they are applied in the same direction, what is the net horizontal force on the sled?
460 N
Titan, Saturn's largest moon, is the only moon in the solar system to have a dense atmosphere. It has an orbital period of 16 days. The radius of Titan's orbit is 1,222,000 km. Rhea is also one of saturn's moons. It has an orbital period of 4.5 days. How far away from Saturn's center is Rhea?
5.3 x 10^5
A mover pushes a 30.0 kg crate across a wooden floor at a constant speed 0.75 ms. If the coefficient of static friction for wood on wood is 0.20, how much force does the mover exert on the crate?
58.8 N
What is the distance traveled by a vehicle in 12 minutes, if its speed is 35 km/h?
7 km
A 1.00 kg ball is attached to a string of 0.50 m and swung in a horizontal circle with a velocity of of 2.00 m/s. Find the centripetal acceleration.
8.0 m/s^2
An athlete executing a long jump leaves the ground at a 28.0 degrees angle and travels 7.80 m. What was the takeoff speed?
9.6 m/s
The acceleration due to Earth's gravity is
9.8 m/s^2
Acceleration is the rate at which an object's speed changes
false
Force is a scalar quantity
false
Inertia is a force
false
Scalar measurements have both magnitude and direction
false
The equilibrate is equal in magnitude and direction to the net force on an object
false
A safe rests on a boat ramp. The ramp is tilted until the safe just starts to slide. The angle at which the safe starts to slide is 33 degrees. What is the coefficient of static friction between the safe and the ramp?
mu=0.64
Which of the following is NOT true?
An object moving at a constant velocity always has a force acting on it
How is displacement different from distance? Under what conditions can an object travel a certain distance and yet its resultant displacement be zero?
Displacement is a vector, it has distance and direction. Distance is a scalar, it just has magnitude. So if you walk 10 miles north and 10 miles south, the vector sum of those displacements is zero, you wind up back where you started. But the distance walked is 20 miles.
The centripetal force on an object in uniform circular motion is calculated using which formula?
Fnet=ma(of c)
Idaho Jo is doing physics experiments throughout the solar system. She travels to each planet and shoots a potato straight up in the air with her potato gun. She uses the same potato on each planet and the initial velocity is the same every time. She repeats the experiment on all 8 planets in the solar system.
Mercury/Mars
"F a on b=-F b on a " is an expression of
Newton's third law
An antelope trots 40m east, then turns at a 45 degree angle and trots 75m southeast. Which choice gives the correct solution for the resultant?
R^2=40^2+70^2-2(40)(70)cos45
A wolf spider runs 75 cm west, then turns and runs 50 cm south. Which choice gives the correct solution for the resultant?
R^2=75^2+50^2
A block with mass 4.4 kg is free to slide along a horizontal frictionless air hockey table. This sliding block is connected by a string and pulley to a second block with mass 2.9 kg that is hanging over the edge of the table. The hanging block will fall, pulling the sliding block to the right. Find the tension in the cord.
T=17.11 N
The correct expression for finding the period of a planet revolving around the Sun is:
T^2+r^3(4pi^2/Gm(ofs))
Mechanics
The branch of applied mathematics dealing with motion and forces producing motion.
Kinematics
The branch of mechanics concerned with the motion of objects without reference to the forces that cause the motion.
Physics
The branch of science that studies matter and energy and their relationships.
Acceleration
The rate at which the velocity of an object changes.
A child throws a baseball upward with an initial velocity of 20 m/s. The child wants to throw the baseball as high as the top of the 20 m tall tree. Is the child successful?
Yes; s=20.41 m
Which of the following system of forces provides the blocks the highest net force?
_____ ---------->| |<----------- 227 N 153 N
A player kicks a football from ground level with a velocity of 27 m/s at an angle of 30 degrees. a) How long is the ball in the air? b) How high does the ball go? c) How far ors the ball go before it hits the ground?
a) 2.76 s b) 9.3 m c) 64 m
A boat heads directly across a river 41 m wide at 3.8 m/s. The current is flowing downstream at 2.2 m/s. a) What is the resultant velocity of the boat? b) How much time does it take the boat to cross the river? c) How far downstream is the boat when it reaches the other side?
a) 4.4 m/s b) 13 s c) 24 m
Which of the following does NOT represent Newton's second law?
a=m/F
Newton's law of universal gravitation states that
objects attract other objects with a force that is directly proportional to the product of their masses, and inversely proportional to the square of the distance between them
Equilibrium can occur
only if the sum of the forces is zero
The normal force on an object always acts
perpendicular to the surface upon which the object is resting
An object that is shot through the air is called a
projectile
To determine the y-component of a projectile's velocity, what operation is performed on the angle of the launch?
sine
An object that has negative acceleration is definitely doing what?
slowing down
Sky divers jump out of a plane of an altitude of 4000m. How much time will pass until they deploy their parachutes of an altitude of 760 m? Assume their air resistance is neglible.
t=25.71 s
When the drag force on an object falling through the air equals the force of gravity, the object has reached
terminal velocity
Tension refers to
the force exerted by a string
The angle of the resultant vector is equal to
the inverse tangent of the quotient of the y-component divided by the x-component of the resultant vector
The sine of an angle is
the length of the side opposite to the angle divided by the length of the hypotenuse
The static friction force is
the minimum force required to overcome static friction and move an object
Kepler's first law states that
the orbits of the planets are elliptical
The normal force (Fn) refers to
the perpendicular contact force exerted by a surface on another object
The speed is represented by
the ratio of the change of position to the time interval during the change
Kepler's second law states that
the speed of a planet's orbit varies depending on which part of the ellipse it isoccupying
Kepler's third law states that
the square of the ration of the periods of any two planets revolving around the Sun is equal to the cube of the ratio of their average distance from the Sun
The path of a projectile trough space is called its
trajectory
The path through space followed by a projectile is called the
trajectory
A Newton is the amount of force applied to a 1 g object that will cause it to have ana celebration of 1 km/s^2
true
A free-body diagram represents forces acting on a system
true
A time interval is a scalar quantity
true
Acceleration is a vector quantity
true
Static friction is exerted on one surface by another when there is no motion between the surfaces
true
The average velocity is defined as the ratio of the change of position to the time interval during which the change occurred
true
The displacement of an object can be calculated by multiplying its velocity and the time interval
true
When a force is a push, the force arrows in a free body diagram point towards the particle
true
The movement of an object at a constant speed around a circular radius is know as
uniform circular motion
Which formula represents final velocity of an object with average acceleration?
vf = vi + aΔt
A diver running 1.8 m/s dives out horizontally from the edge of a vertical cliff and 3.0 s later reaches the water below. How high was the cliff, and how far from its base did the diver hit the water?
x=5.4 m
When an object is in equilibrium, the net force is
zero