Physics Exam 1

Two objects with masses of m1 = 2.10 kg and m2 = 6.30 kg are connected by a light string that passes over a frictionless pulley, as in the figure below. Determine the acceleration of each object.

4.9 m/s^2

A ball is thrown vertically upward with a speed of 28.0 m/s. How high does it rise?

40.0 m

One cubic centimeter (1.0 cm3) of water has a mass of 1.0 ✕ 10−3 kg. Assuming biological substances are 100% water, estimate the mass of a (spherical) cell with a diameter of 1.0 µm.

5.2e-16 kg

For the triangle shown in the figure below what are each of the following? (Let y = 8.00 m and r = 10.0 m. Assume the triangle is a right triangle.) the length of the unknown side x

6.00 m

Two packing crates of masses m1 = 10.0 kg and m2 = 3.10 kg are connected by a light string that passes over a frictionless pulley as in the figure below. The 3.10-kg crate lies on a smooth incline of angle 39.0°. Find the following: the acceleration of the 3.10-kg crate

6.02 m/s^2

A tennis player tosses a tennis ball straight up and then catches it after 2.22 s at the same height as the point of release. Find the maximum height it reaches.

6.06 m

A truck covers 40.0 m in 8.80 s while uniformly slowing down to a final velocity of 3.00 m/s. Find the truck's original speed.

6.09 m/s

In a certain right triangle, the two sides that are perpendicular to each other are 3.10 m and 5.30 m long. What is the length of the third side of the triangle?

6.14 m

A girl delivering newspapers covers her route by traveling 3.50 blocks west, 3.00 blocks north, and then 5.50 blocks east. What is the total distance she travels?

12.00 blocks

An object moves with constant acceleration 3.75 m/s2 and over a time interval reaches a final velocity of 10.0 m/s. If its original velocity is 5.00 m/s, what is its displacement during the time interval?

10.0 m

An object moves with constant acceleration 3.75 m/s2 and over a time interval reaches a final velocity of 10.0 m/s. Initial velocity 5.00 m/s. What is the distance it travels during this interval?

10.0 m

A tennis player tosses a tennis ball straight up and then catches it after 2.22 s at the same height as the point of release. Find the initial velocity and direction of the ball.

10.9 m/s upward

A certain corner of a room is selected as the origin of a rectangular coordinate system. If a fly is crawling on an adjacent wall at a point having coordinates (1.0, 1.3), where the units are meters, what is the distance of the fly from the corner of the room?

1.6 m

A 3.00-kg block starts from rest at the top of a 29.5° incline and slides 2.00 m down the incline in 1.55 s. Find the acceleration of the block.

1.66 m/s^2

A truck covers 40.0 m in 8.80 s while uniformly slowing down to a final velocity of 3.00 m/s. Find the truck's acceleration.

-0.351 m/s^2

A ball is thrown vertically upward with a speed of 28.0 m/s. What is its velocity when it returns to the level from which it started?

-28.0 m/s

A certain freely falling object, released from rest, requires 1.55 s to travel the last 24.5 m before it hits the ground. Find the velocity of the object when it is 24.5 m above the ground.

-8.21 m/s

A tennis player tosses a tennis ball straight up and then catches it after 2.22 s at the same height as the point of release. What are the acceleration and direction of the ball while it is in flight?

-9.8 m/s^2 downward

A tennis player tosses a tennis ball straight up and then catches it after 2.22 s at the same height as the point of release. What is the velocity of the ball when it reaches its maximum height?

0 m/s

In the figure below, m1 = 10.5 kg and m2 = 4.3 kg. The coefficient of static friction between m1 and the horizontal surface is 0.60, and the coefficient of kinetic friction is 0.30. If the system is released from rest, what will its acceleration be? (Enter the magnitude of the acceleration.)

0 m/s^2

A dockworker loading crates on a ship finds that a 35-kg crate, initially at rest on a horizontal surface, requires a 70-N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 52 N is required to keep it moving with a constant speed. Find the coefficients of static and kinetic friction between crate and floor. static friction = _____; kinetic friction = _____

0.20; 0.15

Two forces are applied to a car in an effort to move it, as shown in the figure below. (Let F1 = 400 N 10 degrees west of north and F2 = 350 N east of north. Assume up and to the right are in the positive directions.) What is the resultant vector of these two forces? If the car has a mass of 3,000 kg, what acceleration does it have? Ignore friction.

0.24 m/s^2

A 3.00-kg block starts from rest at the top of a 29.5° incline and slides 2.00 m down the incline in 1.55 s. Find the coefficient of kinetic friction between the box and the incline.

0.371

For the triangle shown in the figure below what are each of the following? (Let y = 8.00 m and r = 10.0 m. Assume the triangle is a right triangle.) the sin of ϕ (between y and r)

0.600

In the figure below, m1 = 10.5 kg and m2 = 4.3 kg. The coefficient of static friction between m1 and the horizontal surface is 0.60, and the coefficient of kinetic friction is 0.30. If the system is set in motion with m2 moving downward, what will be the acceleration of the system? (Enter the magnitude of the acceleration.)

0.76 m/s^2

One cubic centimeter (1.0 cm3) of water has a mass of 1.0 ✕ 10−3 kg. Determine the mass of 1 m3 of water.

1.0e3 kg

An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. Having initially moved upward with a constant velocity, the elevator begins to accelerate downward at 1.50 m/s2. Find T.

1.1e4 N

A ball is thrown upward from the ground with an initial speed of 14.2 m/s; at the same instant, another ball is dropped from a building 18 m high. After how long will the balls be at the same height?

1.27 s

An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. The elevator of part (d) now moves with constant upward velocity of 10 m/s. Find T.

1.2e4 N

For the triangle shown in the figure below what are each of the following? (Let y = 8.00 m and r = 10.0 m. Assume the triangle is a right triangle.) the tangent of θ (between x and r)

1.33

An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. Let the elevator have a mass of 1,275 kg and an upward acceleration of 2.3 m/s2. Find T.

1.5e4 N

An object moves with constant acceleration 3.75 m/s2 and over a time interval reaches a final velocity of 10.0 m/s. If its initial velocity is −5.00 m/s, what is its displacement during this interval?

10.0 m

The eye of a hurricane passes over Grand Bahama Island in a direction 60.0° north of west with a speed of 40.0 km/h. Three hours later, the course of the hurricane suddenly shifts due north, and its speed slows to 27.0 km/h. How far from Grand Bahama is the hurricane 4.20 h after it passes over the island?

149 km

The leg and cast in the figure below weigh 203 N (w1). Determine the weight w2 and the angle α needed so that no force is exerted on the hip joint by the leg plus cast. w2 = _____; α = _____

157 N; 57.5 degrees

An object moves with constant acceleration 3.75 m/s2 and over a time interval reaches a final velocity of 10.0 m/s. Initial velocity -5.00 m/s. What is the total distance it travels during this interval?

16.7 m

A fireman d = 52.0 m away from a burning building directs a stream of water from a ground-level fire hose at an angle of θi = 29.0° above the horizontal as shown in the figure. If the speed of the stream as it leaves the hose is vi = 40.0 m/s, at what height will the stream of water strike the building?

18.0 m

One cubic centimeter (1.0 cm3) of water has a mass of 1.0 ✕ 10−3 kg. Assuming biological substances are 100% water, estimate the mass of a fly. Take a fly to be roughly a cylinder 4 mm long and 2 mm in diameter.

1e-5 kg

Two objects with masses of m1 = 2.10 kg and m2 = 6.30 kg are connected by a light string that passes over a frictionless pulley, as in the figure below. Determine the distance each object will move in the first second of motion if both objects start from rest.

2.45 m

A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 17.0° below the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline with a constant acceleration of 2.75 m/s2 for a distance of 30.0 m to the edge of the cliff, which is 40.0 m above the ocean. Find the length of time the car is in the air.

2.48 s

A 3.00-kg block starts from rest at the top of a 29.5° incline and slides 2.00 m down the incline in 1.55 s. Find the speed of the block after it has slid 2.00 m.

2.57 m/s

A jet airliner moving initially at 2.70 ✕ 102 mi/h due east enters a region where the wind is blowing at 1.00 ✕ 102 mi/h in a direction 25.0° north of east. (Let the x-direction be eastward and the y-direction be northward.) Find the components of the velocity of the jet airliner relative to the air, V_JA. vJA,x = _____; vJA, y = _____

2.70e2 mph; 0 mph

One cubic centimeter (1.0 cm3) of water has a mass of 1.0 ✕ 10−3 kg. Assuming biological substances are 100% water, estimate the mass of a human kidney. Take a kidney to be roughly a sphere with a radius of 4 cm.

2.7e-1 kg

A ball is thrown vertically upward with a speed of 28.0 m/s. How long does it take to reach its highest point?

2.86 s

A ball is thrown vertically upward with a speed of 28.0 m/s. How long does the ball take to hit the ground after it reaches its highest point?

2.86 s

A brick is thrown upward from the top of a building at an angle of 35° to the horizontal and with an initial speed of 10 m/s. If the brick is in flight for 2.8 s, how tall is the building?

22 m

A certain freely falling object, released from rest, requires 1.55 s to travel the last 24.5 m before it hits the ground. Find the total distance the object travels during the fall.

27.9 m

A 4.2-g bullet leaves the muzzle of a rifle with a speed of 332 m/s. What force (assumed constant) is exerted on the bullet while it is traveling down the 0.81-m-long barrel of the rifle?

290 N

A girl delivering newspapers covers her route by traveling 3.50 blocks west, 3.00 blocks north, and then 5.50 blocks east. What are the magnitude and direction of her resultant displacement?

3.61 blocks; 56.3 degrees north of east

A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 17.0° below the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline with a constant acceleration of 2.75 m/s2 for a distance of 30.0 m to the edge of the cliff, which is 40.0 m above the ocean. Find the car's position relative to the base of the cliff when the car lands in the ocean.

30.4 m

Two objects with masses of m1 = 2.10 kg and m2 = 6.30 kg are connected by a light string that passes over a frictionless pulley, as in the figure below. Determine the tension in the string.

30.9 N

An object with mass m1 = 4.70 kg, rests on a frictionless horizontal table and is connected to a cable that passes over a pulley and is then fastened to a hanging object with mass m2 = 11.8 kg, as shown in the figure. Find the tension in the cable.

32.9 N

A jet airliner moving initially at 2.70 ✕ 102 mi/h due east enters a region where the wind is blowing at 1.00 ✕ 102 mi/h in a direction 25.0° north of east. (Let the x-direction be eastward and the y-direction be northward.) What are the speed and direction of the aircraft relative to the ground? magnitude = _____; direction = _____ north of east

363 mph; 6.67 degrees

Two packing crates of masses m1 = 10.0 kg and m2 = 3.10 kg are connected by a light string that passes over a frictionless pulley as in the figure below. The 3.10-kg crate lies on a smooth incline of angle 39.0°. Find the following: the tension in the string

37.8 N

A vector has an x-component of −24.0 units and a y-component of 29.5 units. Find the magnitude and direction of the vector. r = _____; theta = _____ counterclockwise from the +x-axis

38.0 units; 129.1 degrees

A certain corner of a room is selected as the origin of a rectangular coordinate system. A fly is crawling on an adjacent wall at a point having coordinates (3.9, 2.7), where the units are meters. Express the location of the fly in polar coordinates. r = _____; theta = _____

4.7 m; 35 degrees

Two blocks each of mass m = 2.88 kg are fastened to the top of an elevator as in the figure below. If the elevator has an upward acceleration a = 1.60 m/s2, find the tensions T1 and T2 in the upper and lower strings. If the strings can withstand a maximum tension of 94.0 N, what maximum acceleration can the elevator have before the upper string breaks?

6.52 m/s^2

The speed of light is about 3.00 ✕ 10^8 m/s. Convert this figure to miles per hour.

6.71e8 mph

Two blocks each of mass m = 2.88 kg are fastened to the top of an elevator as in the figure below. If the elevator has an upward acceleration a = 1.60 m/s2, find the tensions T1 and T2 in the upper and lower strings. T1 = _____; T2 = _____

65.6 N, 32.8 N

An object with mass m1 = 4.70 kg, rests on a frictionless horizontal table and is connected to a cable that passes over a pulley and is then fastened to a hanging object with mass m2 = 11.8 kg, as shown in the figure. Find the magnitude of the acceleration of each object. a1 = _____; a2 = _____

7.01 m/s^2; 7.01 m/s^2

An artillery shell is fired with an initial velocity of 300 m/s at 54.0° above the horizontal. To clear an avalanche, it explodes on a mountainside 40.5 s after firing. What are the x- and y-coordinates of the shell where it explodes, relative to its firing point? x = _____; y = _____

7.14e3 m; 1.79e3 m

Two forces are applied to a car in an effort to move it, as shown in the figure below. (Let F1 = 400 N 10 degrees west of north and F2 = 350 N east of north. Assume up and to the right are in the positive directions.) What is the resultant vector of these two forces? magnitude= _____; direction = _____ to the right of forward direction

705 N; 8.6 degrees

A 3.00-kg block starts from rest at the top of a 29.5° incline and slides 2.00 m down the incline in 1.55 s. Find the frictional force acting on the block.

9.49 N

A jet airliner moving initially at 2.70 ✕ 102 mi/h due east enters a region where the wind is blowing at 1.00 ✕ 102 mi/h in a direction 25.0° north of east. (Let the x-direction be eastward and the y-direction be northward.) Find the components of the velocity of the air relative to Earth, V_AE. vAE, x = _____; vAE, y = _____

90.6 mph, 42.2 mph

An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. When the elevator is accelerating upward, which is greater, T or w?

T

An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. When the elevator is moving at a constant velocity upward, which is greater, T or w?

both forces are equal

Newton's law of universal gravitation is represented by F = GMm/r^2 where F is the gravitational force, M and m are masses, and r is a length. Force has the SI units kg · m/s2. What are the SI units of the proportionality constant G?

m^3/kgs^2

A jet airliner moving initially at 2.70 ✕ 102 mi/h due east enters a region where the wind is blowing at 1.00 ✕ 102 mi/h in a direction 25.0° north of east. (Let the x-direction be eastward and the y-direction be northward.) Write an equation for velocity of the aircraft relative to the ground.

vJE = vJA + vAE

An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. When the elevator is moving upward, but the acceleration is downward, which is greater, T or w?

w