1 D Motion
You travel 40 meters down a hall and then 40 m back up the hall, the distance you traveled is ____ and your displacement is _____.
80 m, 0 m
How long does it take an object to accelerate from 10 m/s west to 30 m/s west with an acceleration of 2 m/s2?
10 seconds
If a bullet is shot horizontally from a gun at the same time and height that another bullet is dropped, which bullet will hit the ground first?
Both bullets will hit the ground at the same time.
True or False: An object moving a constant velocity has a net external force of zero.
True
If the torque to loosen a nut on the wheel of a car has a magnitude of 90 Nm, what is the minimum force that must be exerted by a mechanic at the end of a 0.40 m wrench to loosen the nut?
F = 225 N
A student runs 4 laps around a circular track with a radius of 3.185 m. It takes her two minutes. What is the student's velocity?
0 m/s (displacement is 0 m)
An object with a non-zero force acting on it is definitely accelerating. True or False?
False
What is inertia? Which of the following has a greater inertia: a feather or a train?
Inertia is the tendency of an object to resist a change in its motion; the train would have greater inertia; inertia correlates with an object's mass.
A woman is pushing a grocery cart. How does the magnitude of the force exerted on the cart by the woman compare to the force exerted on the woman by the cart?
The force exerted on the cart by the woman = the force on the woman by the cart.
If a car rolls across a parking lot with a constant velocity and an applied force of 150 N, what is the force of friction in the opposite direction?
Ff = 150 N
A student walks 10 meters in 3 seconds then stops for 2 seconds. Then the student walks 20 meters in the same direction in 5 seconds. What is the average speed for the entire walk?
s = 3 m/s
What is the acceleration of an object thrown upwards under the influence of gravity?
a = - 9.8 m/s2
An object experiencing projectile motion has a ____ horizontal velocity.
constant
If a 3000 kg car crashes into a 10,000 kg truck, how does the force on the car compare to the force on the truck?
The force exerted by the car on the truck and the truck on the car are the same.
An astronaut weighs 800 n at the Earth's surface. If we were to double his distance from the Earth's center, what would his new weight be?
200 N
The distance can be less than the displacement. True or False?
False
A flower pot falls off a window sill 20 m above the sidewalk. What is the velocity of the flower pot when it hits the ground? How long is it in the air?
vf = -19.8 m/s; t = 2.02 s
A rock falls from a 125 m tall cliff. What is the final velocity of the rock and how long will it be in the air?
vf = - 49.5 m/s or 49.5 m/s downward; t = 5.1 s
A force is a ______ quantity. Forces cause a change in an object's _____. The unit of a force is ___.
vector; motion or acceleration; N
A 45 kg chair initially at rest on a horizontal surface requires 365 N of force to set it in motion. What is the coefficient of static friction?
uk = 0.83
An ant crawls 1.2 m to the right in 20 seconds and then 0.5 m to the left in 10 seconds. What is the ant's total displacement and velocity?
displacement = 0.7 m right and v = 0.023 m/s
A man skydives out of a small airplane. Assuming no air resistance, how long does it take him to reach a velocity of 200 m/s? How far does he fall during this time?
t = 20.4 seconds, -2039 m or 2039 m downward
A marker rolls off a 1.5 meter high desk and hits the ground 0.33 meters away. What is the resultant velocity of the marker when it hits the ground?
VR = 5.42 m/s downward and to the right
Draw a free-body diagram of an object with a 3245 N force due to gravity, a 2533 N upward force, a 670 N applied force to the right, and a 325 N force of resistance. What is the magnitude of the net external force? If the mass of the object is 200 kg, what is the magnitude of the acceleration?
Fnet = 791 N down and to the right
a = 3.96 m/s2
A 0.020 kg stopper on a string is being whirled around in a circle with a radius of 0.75 meters. If it takes the stopper 0.59 seconds to complete one circle, what is the magnitude of the force on the stopper?
Fc = 1.7 N