Units of Measure
What is the approximate mass of an automobile?
10^3 kg
While pushing a very heavy box, Derek notices that it was much harder for him to get the box to start moving than it was for him to get the box to continue to move once it had started. This is an example of which mechanics principle?
Newton's first law
A force of 6.0 newtons changes the momentum of a moving object by 3.0 kilogram∙meters per second. How long did the force act on the mass?
.5 s
A spring with a spring constant of 80 newtons per meter is displaced 0.30 meter from its equilibrium position. The potential energy stored in the spring is
3.6j
What is the current through a wire if 240 coulombs of charge pass through the wire in 2.0 minutes?
2.0 A
An egg is dropped 'from a third-story window. The distance the egg falls from the window to the ground is closest to?
10^1 m
A student is standing in an elevator that is accelerat- ing downward. The force that the student exerts on the floor of the elevator must be
Less than the weight of the student when at rest.
A 70-kilogram hockey player skating east on an ice rink is hit by a 0.1-kilogram hockey puck moving to- ward the west. The puck exerts a 50-newton force toward the west on the player. Determine the mag- nitude of the force that the player exerts on the puck during this collision.
50 N
Which quantity is a measure of the rate at which work is done?
Power
What is the net electrical charge on a magnesium ion that is formed when a neutral magnesium atom loses two electrons?
-3.2 × 10-19 C
A car traveling on a straight road at 15 meters per second accelerates uniformly to a speed of 21 meters per second in 12 seconds. The total distance traveled by the car in this 12-second time interval is
216 m
A 0.50-kilogram cart is rolling at a speed of 0.40 meter per second. If the speed of the cart is doubled, the inertia of the cart is
Unchanged
A 0.149-kilogram baseball, initially moving at 15 me- ters per second, is brought to rest in 0.040 second by a baseball glove on a catcher’s hand. The magnitude of the average force exerted on the ball by the glove is
56 N
The driver of a car made an emergency stop on a straight horizontal road. The wheels locked and the car skidded to a stop. The marks made by the rubber tires on the dry asphalt are 16 meters long, and the car’s mass is 1200 kilograms.
Determine the weight of the car
11,800 N
Two oppositely charged parallel metal plates, 1.00 centimeter apart, exert a force with a magnitude of 3.60 × 10-15 newton on an electron placed between the plates. Calculate the magnitude of the electric field strength between the plates.
2.25×10^4 N/C
A golf ball is hit with an initial velocity of 15 meters per second at an angle of 35° above the horizontal. What is the vertical component of the golf ball’s ini- tial velocity?
8.6 m/s
A 400-newton girl standing on a dock exerts a force of 100 newtons on a 10,000-newton sailboat as she pushes it away from the dock. How much force does the sailboat exert on the girl?
100 Newton’s
An 8.00-kilogram ball is fired horizontally from a 1.00 × 103-kilogram cannon initially at rest. After hav-
ing been fired, the momentum of the ball is 2.40 × 103 kilogram∙meters per second east.
Calculate the magnitude of the cannons velocity after the ball is fired
2.4 m/s
A 5-newton force causes a spring to stretch 0.2 meter. What is the potential energy stored in the stretched spring?
.5 J
An electron is accelerated through a potential difference of 2.5 × 10^4 volts in the cathode ray tube of a computer monitor. Calculate the work, in joules, done on the electron.
4.0e^-15J
In a 4-kilometer race, a runner completes the first kilometer in 5.9 minutes, the second kilometer in 6.2 minutes, the third kilometer in 6.3 minutes, and the final kilometer in 6 minutes. The average speed of the runner for the race is approximately
.16 km/min
A manufacturers advertisement claims that their 1,250 kilograms sports car can accelerate a level road from 0 to 60 in 3.75 seconds
Determine the acceleration in meters per second, of the car according to the advertisement.
7.15 m/s2
On a snow-covered road, a car with a mass of 1.1×103 kilograms collides head-on with a van having a mass of 2.5×103 kilograms traveling at 8.0 meters per second. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collision. [Neglect friction.]
18 m/s
A 70-kilogram cyclist develops 210 watts of power while pedaling at a constant velocity of 7.0 meters per second east. What average force is exerted east- ward on the bicycle to maintain this constant speed?
30 N
Two small identical metal spheres, A and B, on insulated stands, are each given a charge of +2.0 × 10-6 coulomb. The distance between the spheres is 2.0 × 10-1 meter. Calculate the magnitude of the electro- static force that the charge on sphere A exerts on the charge on the sphere B
9.0 × 10^ -1 N