practice problems for exam 1
a plane is landing at a speed of 50 m/s. the plane is 1000 m from the runway. the plane is descending at an angle of 20 degrees. at a part of a stunt for a movie, a jeep wants to travel directly underneath the plane all the way to the runway. what speed will the jeep need to travel? -50 m/s -(50 m/s) sin 20 -(50 m/s) cos 20 -(50 m/s) / sin 20 -(50 m/s) / cos 20
(50 m/s) cos 20
in a vacuum chamber, on the surface of the earth, a feather and a hammer fall at the same rate. what can you say about the force of gravity Fg, acting on the hammer and the feather? -Fg is greater on the feather -Fg is greater on the hammer -Fg is zero on both due to vacuum -Fg is equal on both always -Fg is zero on both always
Fg is greater on the hammer
a soccer ball is kicked at an initial speed of 20.0 m/s at an angle 30 degrees above the horizontal. what are the horizontal (x) and vertical (y) components of the initial velocity (just after the ball leaves the foot)? -Vx = 10.0 m/s ; Vy = 10.0 m/s -Vx = 17.3 m/s ; Vy =17.3 m/s -Vx = 10.0 m/s ; Vy = 17.3 m/s -Vx = 17.3 m/s ; Vy = 10.0 m/s -Vx = 20.0 m/s ; Vy = 10.0 m/s
Vx = 17.3 m/s ; Vy = 10.0 m/s
a.) a ball is thrown straight up with initial velocity v0 from the top of (and at the edge of) a tall building. it goes up a distance h=60 m, then comes back down again. take +direction upward. what was v0? b.) what is the velocity of the ball just before it hits the ground L=20 m below the top of the building? c.) how long does the ball take to go up its peak and then fall down to the ground, 20 m below the top of the building?
a.) +34.3 m/s b.) -39.6 m/s c.) 7.55 s
a bullet is fired through a wooden board with a thickness of 11.0 cm. the bullet hits the board perpendicular to it, and with a velocity of +430 m/s. the bullet then emerges on the other side of the board with a velocity of +387 m/s. assuming constant acceleration of the bullet while inside the wooden board : a.) calculate the acceleration b.) calculate the total time the bullet is in contact with the board
a.) -1.60 x 10^-5 m/s^2 b.) 2.69 x 10^-4 s
a.) calculate the force needed to bring a 860 kg car to rest from a speed of 98.0 km/h in a distance of 139 m b.) suppose instead the car hits a concrete abutment at full speed and is brought to a stop in 1.64 m. calculate the force exerted on the car and compare it with the force found in part (a). i.e, take the ratio of the force when the car hits the concrete abutment to that in part (a)
a.) -2.29 x 10^3 N b.) force : -1.94 x 10^5 N ; ratio : 84.8
a 3.18 kg ball is attached to a ceiling by a 1.40 m long string. the height of the room is 5.90 m. a.) what is the gravitational potential energy of the ball relative to the ceiling? b.) what is the gravitational potential energy of the ball relative to the floor? c.) what is the gravitational potential energy of the ball relative to a point at the same elevation as the ball?
a.) -4.36 x 10^1 J b.) 1.40 x 10^2 J c.) 0.00 J
2x + 4y = 16 3x - 2y = 0 a.) what is the value of x? b.) what is the value of y?
a.) 0 b.) 4
a.) you are standing on the ground outside walter hall. you throw a ball straight up. just after it leaves your hand, the ball is traveling at 15.0 m/s. what is the speed of the ball at the moment the ball reaches maximum height? b.) what is the acceleration of the ball (both magnitude and direction) at the moment the ball is at maximum height?
a.) 0 m/s b.) 9.80 m/s^2
a toy car is pushed horizontally off the coffee table with just the right speed to stick it in between the cushions of a living room chair. the chair is 0.35 m from the edge of the table. the crack between the cushions is 0.05 m below the level of the coffee table a.) how much time is the car in free fall? b.) how fast was the toy car pushed to hit the middle of the crack?
a.) 0.101 s b.) 3.46 m/s
a stone thrown horizontally from a height of 6.12 m hits the ground at a distance of 11.50 m. a.) calculate the initial speed of the stone b.) calculate the speed of the stone as it hits the ground.
a.) 1.03 x 10^1 m/s b.) 1.50 x 10^1 m/s
a cannon ball is shot straight upward with a velocity of 57.50 m/s. a.) how high is the cannon ball above the ground 2.30 seconds after it is fired? b.) how much time does it take for the cannon ball to reach maximum height? c.) what is the maximum height attained by the cannon ball?
a.) 1.06 x 10^2 m b.) 5.87 sec c.) 1.69 x 10^2 m
suppose you kick a ball. just after it leaves your foot, it is traveling at a velocity of v=18.2 m/s at an angle = 26.6 degrees. a.) what is the x component of the velocity just after the ball leaves your foot? b.) what is the y component of the velocity just after the ball leaves your foot?
a.) 16.2 m/s b.) 8.14 m/s
x = a (sqrt. b) / c a.) if a is doubled while b and c are held constant, the new value of x will be ___ times the original value b.) if c is cut in half while a and b are held constant, the new value of x will be ___ times the original value c.) if b is quadrupled while a and c are held constant, the new value of x will be ___ times the original value
a.) 2 b.) 2 c.) 2
suppose a 332 g kookaburra picks up a 82.0 g snake and raises it 2.50 m from the ground to a branch. a.) how much work did the bird do on the snake? b.) how much work did it do to raise its own center of mass to the branch?
a.) 2.01 J b.) 8.13 J
a.) 4 workers can build a small barn in 12 days. how many workers are needed if we want to build 5 in the same length of time (12 days)? b.) how many workers are needed if we want to accelerate construction and build one barn in 3 days? c.) on the other hand, if we want to build 5 barns in 3 days, how many workers do we need?
a.) 20 b.) 15 c.) 300
a.) you are standing on the roof of Clippinger. you hold out your arm and release a ball with a mass of 0.150 kg (it starts at rest). 1.00 sec after you release it, its velocity is 9.80 m/s downward. (think about what that means for the acceleration) what is its velocity 2.38 sec after you release it? b.) you hold out your arm and release a second ball with a mass of 0.300 kg. what is its velocity 2.38 sec after you release it?
a.) 23.3 m/s ; downward b.) 23.3 m/s ; downward
a small pumpkin is launched from a very versatile catapult at a variety of speeds and angles. the angles are measured relative to the horizontal. rank each of the following trials by the maximum height reached by the pumpkin (1=highest) a.) speed = 13.8 m/s ; angle = 67.1 b.) speed = 138.7 m/s ; angle = 11.4 c.) speed = 27.6 m/s ; angle = 36.5 d.) speed = 24.4 m/s ; angle = 68.1
a.) 4 b.) 1 c.) 3 d.) 2
x = [(a(b^2))/(c)] a.) if b is doubled while a and c are held constant, the new value of x will be ___ times the original value b.) if a is doubled while b and c are held constant, the new value of x will be ___ times the original value c.) if c is cut in half while a and b are held constant, the new value of x will be ___ times the original value
a.) 4 b.) 2 c.) 2
x + y = 9 2x + y = 13 a.) what is the value of x? b.) what is the value of y?
a.) 4 b.) 5
you lift a 41.30 kg box from the floor onto a shelf 0.97 m above the floor. if you lift the box with a constant speed.. a.) what is the magnitude of the force you exert on the box? is it upward or downward? b.) what is the work you do on the box? c.) what is the magnitude of the change in potential energy of the box? does it increase or decrease?
a.) 404.74 N ; upward b.) 392.60 J c.) 392.60 J ; increase
a rope is pulling horizontally to the right on a box of weight 57.0N which is sliding across the floor at a constant speed. the coefficient of kinetic friction between the floor and the box is 0.303. a.) what is the magnitude and direction of the normal force from the floor acting on the box? b.) what is the magnitude and direction of the frictional force acting on the box? c.) what is the magnitude of the tension in the rope which is pulling the box?
a.) 57.0 N ; up b.) 17.3 N ; left c.) 17.3 N
a kangaroo can jump over an object 1.90 m high. a.) calculate its vertical speed when it leaves the ground b.) how long is it in the air?
a.) 6.10 m/s b.) 1.25 s
you travel 6.33 km to the east. you then turn around and travel 7.03 km in a direction/degree of 35.0 north of east. a.) what is the x component of the first part of the trip? b.) what is the y component of the first part of the trip? c.) what is the x component of the second part of the trip? d.) what is the y component of the second part of the trip? e.) what is the x component of the displacement for the overall trip (R)? f.) what is the y component of the displacement for the overall trip (R)? g.) what is the magnitude of the displacement for the overall trip (R)? h.) what is the direction of the displacement for the overall trip (R)?
a.) 6.33 km b.) 0.00 km c.) 5.76 km d.) 4.03 km e.) 12.09 km f.) 4.03 km g.) 12.74 km h.) 18.44 deg N of E
a powerful motorcycle can accelerate from rest to 30.6 m/s (110 km/h) in only 3.92 s. a.) what is its average acceleration? b.) how far does it travel in that time?
a.) 7.79 m/s^2 b.) 59.9 m
a firefighter is spraying water on a building. water leaves the hose at 35 m/s and an angle of 30 deg. above the horizontal. the nozzle of the hose is 1.0 m above the ground, and the building is 22 m away. the building is 40 m tall. a.) what are the horizontal (x) and vertical (y) components of the initial velocity? b.) how much time does it take for the water to reach the building? c.) at what height above the ground does the water hit the building? d.) in what vertical direction is the water traveling when it hits the building? e.) what is the speed of the water just before it hits the building?
a.) Vx0 = 30.3 m/s ; Vy0 = 17.5 m/s b.) 0.73 s c.) 11.2 m d.) up e.) 32.0 m/s
a water balloon is launched at a speed of 11 m/s from ground level at an angle of 50 deg. above the horizontal. the water balloon is launched towards a bystander who is 1.5 m tall and standing 2 m away. a.) what are the horizontal and vertical components of the initial velocity? b.) by how much does the water balloon clear the person's head? c.) how fast is the balloon traveling when it is directly over the person's head?
a.) Vx0 = 7.07 m/s ; Vy0 = 8.43 m/s b.) 0.5 m c.) 9.07 m/s
a woodpecker's brain is specially protected from large decelerations by tendon like attachments inside the skull. while pecking on a tree, the woodpecker's head comes to a stop from an initial velocity of 0.590 m/s in a distance of only 1.90mm. a.) find the acceleration and in multiples of g (g=9.80 m/s^2) b.) calculate the stopping time c.) the tendons cradling the brain stretch, making its stopping distance 3.99 mm (greater than the head, and hence, less deceleration of the brain). what is the brain's deceleration, expressed in multiples of g?
a.) acceleration = -91.6 m/s^2 ; multiples of g = -9.35 b.) 0.00644 s c.) -4.45
two steel balls are released at the same time. ball A is dropped from rest. ball B is shot horizontally from the same height with initial horizontal velocity v. a.) which ball hits the ground first? b.) which ball is traveling the fastest before it hits the floor?
a.) both hit at the same time b.) ball B
an object is tossed into the air. consider the direction of acceleration as the object is traveling upwards, turns around and is traveling downward. which of the following statements is true? -acceleration is upward when the object is traveling up ; downward when traveling down -acceleration is downward when the object is traveling up ; downward when traveling down -acceleration is upward when object is traveling up ; upward when traveling down -acceleration is downward when object is traveling up ; upward when traveling down
acceleration is downward when the object is traveling up ; downward when traveling down
what are the x and y components of the acceleration for an object undergoing projectile motion?
ax : 0 m/s^2 ay :-9.80 m/s^2
consider a cart on a horizontal frictionless table. once the cart has been given a push and released, what will happen to the cart? -slowly come to a stop -continue with constant acceleration -continue with decreasing acceleration -continue with constant velocity -immediately come to a stop
continue with constant velocity
suppose you travel a distance of 5.20 km due east and then travel a distance of 8.30 km due north. if you were to go back to your starting point and travel in a straight line to your previous ending point, what would be the distance and the direction (degrees) in which you would travel?
distance = 9.79 km direction = 57.9 deg
e37 x e-31 = e?
e6
true or false : positive work is done when a force is applied perpendicular to the displacement
false
this morning, joe took his dog to the park on a long leash. on the way, the dog took many side trips chasing other dogs. when joe and his dog, finally arrive at the park. which one of the following statements is true? -joe and the dog traveled the same distance -the dog's displacement was larger than joe's displacement -joe and the dog have the same displacement -the dog's displacement was smaller than Joe's displacement
joe and the dog have the same displacement
a jet plane lands with a velocity of +100m/s and with full brakes on has an acceleration of -5.0m/s^2. can this plane land on a small island airport where the runway is 800 m long?
no
you put your book on the bus seat next to you. when the bus stops suddenly, the book slides forward off the seat. why? -a net force acted on it -no net force acted on it -it remained at rest -it did not move, but only seemed to -gravity briefly stopped acting on it
no net force acted on it
you are on an elevator which is accelerating upward at a rate of 2.00 m/s^2. your mass is 80.0 kg, and the elevator has a mass of 500 kg. how does the normal force (the force of the elevator floor upward on you) compare to your weight? -normal force > weight -normal force = weight -normal force < weight
normal force > weight
the normal force from a surface is always ______ to the surface
perpendicular
rank the following values in increasing order (1=lowest) a.) 1 cm b.) 1 nm c.) 1 Gm d.) 1 m e.) 1 Mm f.) 1 mm
1.) 1 nm 2.) 1 mm 3.) 1 cm 4.) 1 m 5.) 1 Mm 6.) 1 Gm
you are driving home at night traveling at +30 m/s when a deer jumps out in the road 150 m ahead and freezes in your headlights. after a reaction time of t, you apply the brakes to produce a constant acceleration of -4.0 m/s^2? what is the maximum reaction time allowed in order to not hit the deer?
1.25 s
what distance in kilometers is equivalent to 793 miles?
1.28e3 km
an observer, whose eyes are 1.75 m above the ground, is standing 30.4 m away from a tree. the ground is level, and the tree is growing perpendicular to it. the observer's line of sight with the treetop makes an angle of 20.7 degrees above the horizontal. how tall is the tree?
1.32 x 10^1 m
(5e33)(3e-27) = ?
1.50e7
a shopper in a supermarket pushes a cart with a force of 38.0 N directed at an angle of 27.0 deg. downward from the horizontal. find the work done by the shopper as he moves horizontally along a 49.0 m length of aisle
1.66 x 10^3 J
the initial velocity of a 2.27 kg block sliding down a frictionless inclined plane is found to be 1.55 m/s. then 1.49 s later, it has a velocity of 6.33 m/s. what is the angle of the plane with respect to the horizontal?
1.91 x 10^1 degrees
a box with a mass of 5kg is just sitting on the flat bed of a truck (it is not tied down in anyway). the truck accelerates at 2 m/s^2, as does the box (so it's not slipping). the coefficient of frictions between the box and the bed of the truck are mu(s)=0.6 and mu(k)=0.4. what is the magnitude of the frictional force acting on the box?
10 N
an olympic class sprinter starts a race with an acceleration of 3.90 m/s^2. what is her speed 2.70 s later?
10.5 m/s
runner b travels a distance of 57.0 m at a speed of 5.37 m/s. how much time did it take runner b to run this distance?
10.61 s
x^2 + (-1.7)x + (-43.5) = 0 ; using the quadratic formula, you will come up with two solutions for x. what is the value of x which is positive?
11
just before it hits the ground, a rock is traveling with a horizontal component of the velocity equal to 10 m/s to the east and a vertical component of the velocity equal to 5 m/s downward. how fast is the rock traveling? (what is the magnitude of the velocity?) -8.7 m/s -11.2 m/s -13.5 m/s -14.3 m/s -15.0 m/s
11.2 m/s
in an action movie, the heroine is supposed to jump with a motorcycle from the roof of one skyscraper to another one. the roof of the second skyscraper is h=8 meters lower, and the gap between the buildings is d=18 meters wide. both roofs are horizontal and flat. neglecting air resistance, what minimum initial speed would she need to make the jump?
14.1 m/s
you run 322 m to the east, then turn around and run 161 to the west. what is the magnitude of your displacement during the run described?
161 m
a large crate weighs 100N. you push straight down on the top of the crate with a force of 75N. what is the force with which the floor pushes up on the crate?
175N
a rescue helicopter is hovering over a person whose boat has sunk. one of the rescuers throws a life preserver straight down to the victim with an initial velocity of 1.40 m/s and observes that it takes 1.80 s to reach the water. how high above the water was the preserver released? (note that acceleration equal to that of gravity is reasonable)
18.4 m
you travel 10 km south, 30 km 60 degrees north of east and then 5 km west. how far and in what direction are you away from where you started?
18.9 km ; 58 degrees north of east
a ball is released from the roof of a building that is 20 m tall. how fast is the ball traveling just before it hits the ground? (assume +y is upwards)
19.8 m/s
how many sig figs in 0.035?
2
a car starting from rest accelerates at a rate of 9.80 m/s^2. presume it travels in a straight line and the acceleration is in the direction of travel. how much time does it take to travel 20.0 m?
2.02 s
when the rubber band in a slingshot is stretched, it obeys Hooke's law. suppose that the spring constant for the rubber band is k=43.2 N/m. when the rubber band is pulled back with a force of 9.36 N, how far does it stretch?
2.17 x 10^-1 m
a hiker, who weighs 978 N is strolling through the woods and crosses a small horizontal bridge. the bridge is uniform, weighs 3640 N, and rests on two concrete supports, one at each end. he stops 1/5 of the way along the bridge. what is the magnitude of the force that a concrete support exerts on the bridge at the near end?
2.60 x 10^ 3 N
a jet plane lands with a velocity of +100m/s and with full brakes on has an acceleration of -5.0m/s^2. from the instant it touches the runway, how long (in s) does it take before the plane comes to a complete stop?
20 s
a ball of mass 2.0 kg is hanging from a string. the ball is accelerating upward at 1 m/s^2. what is the force that the string is exerting on the ball?
21.6 N
a car travels at a velocity of 25 m/s and 30 deg. N of E. which value represents the east component of the velocity? -21.6 m/s -25 m/s -27.1 m/s -31.5 m/s
21.6 m/s
how many hours are equivalent to 88500 seconds?
24.6 hours
you measure the distance between two trees to be 7.29 m. what is the distance in inches?
287 inches
a box with a weight of 10N starts at rest. a 2N force is exerted on the box. mu(s)=0.4 and mu(k)=0.3. what is the magnitude and direction of the frictional force?
2N to the left
how many sig figs in 7.40?
3
a block of weight 41.1N is hanging from a rope. the tension in the rope is 53.9N, pulling upward on the block. what is the magnitude and direction of the acceleration of the block?
3.05 m/s^2 upward
a hiker travels 7.2 in a direction of 60 degrees north of east. how far east did they travel?
3.6 km
when a 83.5 kg adult uses a spiral staircase to climb to the second floor of his house, his gravitational potential energy increases by 1.84x10^3 J. by how much does the potential energy of a 17.2 kg child increase when the child climbs a normal staircase to the second floor?
3.79 x 10^2 J
a ball is thrown up into the air at a speed of 25 m/s. how high does the ball travel? (assume +y is upward)
31.9 m
suppose a brick has a mass of 3.30 kg. what is the brick's weight at the surface of the earth?
32.3 N
you and a friend are sliding a large 100 kg box across the floor. your friend pulls to the right with a force of 250N. the frictional force of the floor opposes the motion with a force of 500N. the box has an acceleration of 1.0 m/s^2 to the right. what is the force that you exerted on the box?
350N to the right
a box weighing 10N is moving to the right under the influence of a 10N horizontal force. mu(s)=0.4 and mu(k)=0.3. what is the magnitude and direction of the frictional force?
3N to the left
7 + 2x = 15 ; x=?
4
how many sig figs in 1200. ?
4
a car is traveling 50 mph in a direction 60 degrees north of east. how much time will it take to travel 100 miles east? -1 hour -2 hours -3 hours -4 hours
4 hours
a car is traveling 60 mph in a direction 60 degrees north of east. how much time will it take to travel 120 miles east?
4 hours
suppose you travel a distance of 6.78 km at an angle of 52.8 degrees north of east. how far east did you travel?
4.10 km
standing at the edge of the track, you are observing two runners. runner a travels a distance of 81.1 m over a time of 19.2 s. what is the average speed of runner a?
4.22 m/s
an elevator (cabin mass 520 kg) is designed for a maximum load of 3500 kg, and to reach a velocity of 2.8 m/s in 3s. for this scenario, what is the tension the elevator rope has to withstand?
4.32 x 10^4 N
A dolphin leaps out of the water at an angle of 32.6° above the horizontal. The horizontal component of the dolphin's velocity is 7.45 m/s. Calculate the magnitude of the vertical component of the velocity.
4.76 m/s
you drive 40 mi due west, then switch drivers. your friend then drives 25 mi due north. how far away and in what direction are you from where you started?
47 miles 32 degrees north of west
you run 322 m to the east, then turn around and run 161 to the west. what is your total distance traveled?
483 m
how many sig figs in 12.003?
5
suppose you travel a distance of 6.78 km at an angle of 52.8 degrees north of east. how far north did you travel?
5.40 km
a bucket of water weighs 55.8N at the surface of the earth. what is the mass of the bucket and water?
5.69 kg
a bullet is fired from a rifle that is held 1.61 m above the ground in a horizontal position. the initial speed of the bullet is 1118 m/s. calculate the time it takes for the bullet to strike the ground
5.73 x 10^-1 s
the gondola ski lift at a colorado ski resort is 2647 m long. on average, the ski lift rises 12.6 degrees above the horizontal. how high is the top of the ski lift relative to the base?
5.77 x 10^2 m
when opening a door, you push on it perpendicularly with a force of 55.4 N at a distance of 0.920 m from the hinges. what torque are you exerting relative to the hinges?
51.0 N*m
if a car is traveling 24.7 m/s, how fast is it traveling in miles/hour?
55.3 mph
a block of mass 3.03 kg is hanging from a rope. the tension in the rope is 11.5N, pulling upward on the block. what is the magnitude and direction of the acceleration of the block?
6.01 m/s^2 downward
a hiker travels 7.2 km in a direction of 60 degrees north of east. how far north did they travel?
6.2 km
a professor drives off with his car (mass 840 kg), but forgot to take his coffee mug (mass 0.45 kg) off the roof. the coefficient of static friction between the mug and the roof is 0.7, and the coefficient of kinetic friction is 0.5. what is the maximum acceleration of the car, so the mug does not slide off?
6.87 m/s^2
e37 / e-31 = e?
68
4 + (18/x-1) = 7 ; x=?
7
You drive 12.50 km in a straight line in a direction 41° east of north. Find the distance you would have to drive straight east and then straight north to arrive at the same point
8.20 km east ; 9.43 km north
a major league pitcher can throw a baseball in excess of 40.0 m/s. if a ball is thrown horizontally at this speed, how much will it drop by the time it reaches a catcher who is 16.6 m away from the point of release?
8.44 x 10^-1 m
a box weighing 100N is pulled up to the right by a rope with a force of 10N at an angle of 30 deg. above the horizontal. there is a frictional force of 3N to the left. what is the acceleration of the box? what is the normal force from the table on the box?
95N
a ball of mass 2.0 kg is hanging from a string. the ball is traveling upward but slowing down. how does the force from the string (the tension) compare to the weight of the ball? -tension is greater than weight -tension is equal to weight -tension is less than weight
tension is less than weight
a box of weight 100N is at rest on a floor where mu(s)=0.5. a rope is attached to the box and pulled horizontally with tension =30 N. which way does the box move?
the box does not move
describe what is meant by the tail of a vector, the head of a vector and the magnitude of a vector
the tail of a vector is simply the end without the pointy head. the head of the vector is the end with the arrow. the magnitude of a vector is the size of the vector
an object is tossed into the air. consider the velocity and acceleration at the point when the object reaches its maximum height. which of the following statements is true? -the velocity is zero and the acceleration is zero -the velocity is non zero and the acceleration is zero -the velocity is zero and the acceleration is non zero -the velocity is non zero and the acceleration is non zero
the velocity is zero and the acceleration is non zero
a book is lying at rest on a table. the book will remain at rest because : -there is a net force but the book has too much inertia -there are no forces acting on it at all -it does move, but too slowly to be seen -there is no net force on the book -there is a net force, but the book is too heavy to move
there is no net force on the book
two objects are accelerating over a time period of 6 seconds. a toy rocket changes its velocity from 140 m/s to 150 m/s. a bicyclist changes their velocity from 5 m/s to 15 m/s. which has the greatest acceleration? -the rocket has the greater acceleration -the bicyclist has the greater acceleration -they both have the same acceleration
they both have the same acceleration
true or false : a force acts towards the right while the object moves to the left. the work done by the force is negative.
true
true or false : a vertical force acts on a mass while it moves horizontally (but not vertically). no work is done by the vertical force
true
consider standing first on the surface of the earth and then on the surface of the moon. what can you say about your mass?
your mass is the same in both places
a hockey puck slides on ice at a constant velocity. what is the net force acting on the puck? -more than its weight -equal to its weight -less than its weight but more than zero -depends on the speed of the puck -zero
zero
suppose a piece of paper has an area of 151 square centimeters. what is the area of the paper in square meters?
0.0151 m^2
6 - 3x = 18 ; x=?
-4
you and a friend are sliding a large 100 kg box across the floor. your friend pulls to the right with a force of 250N. you push to the right with a force of 300N. the frictional force of the floor opposes the motion with a force of 500N. what is the acceleration of the box?
0.5 m/s^2 to the right
an object glides on a horizontal tabletop with a coefficient of kinetic friction of 0.55. if its initial velocity is 4.1 m/s, how long does it take for the object to come to rest?
0.76 s
you are pulling a crate across the floor. the crate has a mass of 68.0 kg. you exert a horizontal force of 121 N to the right. friction exerts a force of 64.0N to the left. what is the magnitude and direction of the acceleration of the crate?
0.838 m/s^2 ; right
your friend is running at a velocity of 4.160 m/s to the east. when they pass a sign on the sign on the road they increase their velocity to 6.360 m/s (still traveling east) over a time of 2.570 s. what is their average acceleration over the 2.570 s time period?
0.856 m/s^2
The altitude of a hang glider is increasing at a rate of 6.98 m/s. At the same time, the shadow of the glider moves along the ground at a speed of 14.1 m/s when the sun is directly overhead. Calculate the magnitude of the glider's velocity.
15.7 m/s
a basketball referee tosses the ball straight up for the starting tip off. at what velocity must a basketball player leave the ground to rise 1.19 m above the floor in an attempt to get the ball?
4.83 m/s
a block of weight 47.9N is hanging from a rope. the tension from the rope is pulling upward on the block. the block is accelerating downward at a rate of 1.26 m/s^2. what is the magnitude of the tension in the rope?
41.7N
