PHYS-131 Test 1

A ball is fired at an angle of 45°, the angle that yields the maximum range in the absence of air resistance. What is the ratio of the ball's maximum height to its range?

0.25

An apple crate with a weight of 225 N accelerates along a frictionless surface as the crate is pulled with a force of 14.5 N as shown in the drawing.What is the horizontal acceleration of the crate?

0.597 m/s2

A brick is dropped from rest from a height of 4.9 m. How long does it take the brick to reach the ground?

1.0 s

A train with a constant speed of 16 m/s passes through a town. After leaving the town, the train accelerates at 0.33 m/s2 until it reaches a speed of 35 m/s. How far did the train travel while it was accelerating?

1.5 km

Complete the following statement: The ration 1 Milligram/ 1 Kilogram is equal to

10^-6

A 8-kg block is set moving with an initial speed of 6 m/s on a rough horizontal surface. If the force of friction is 12 N, approximately how far does the block travel before it stops?

12 m

A train with a constant velocity of +28.6 m/s approaches a small town . The operator applies the brake, reducing the train's velocity to +11.4 m/s. If the average acceleration of the train during braking is -1.35 m/s2, for what elapsed time does the operator apply the brake?

12.7 s

A 3.0m ladder leans against a wall and makes an angle with the wall o 28 degrees as shown in the drawing. What is the height h above the ground where the ladder makes contact with the wall ?

2.6

Town A lies 20 km north of town B. Town C lies 13 km west of town A. A small plane flies directly from town B to town C. What is the displacement of the plane?

24 km, 57° north of west

In the process of delivering mail, a postal worker walks 161 m, due east from his truck. He then turns around and walks 194 m, due west from his truck. What is the worker's displacement relative to his truck?

33 m, due west

A rope connects boat A to boat B. Boat A starts from rest and accelerates to a speed of 9.5 m/s in a time t = 47 s. The mass of boat B is 540 kg. Assuming a constant frictional force of 230 N acts on boat B, what is the magnitude of the tension in the rope that connects the boats during the time that boat A is accelerating?

340 N

Which one of the following choices is equivalent to 44.5 mm ?

4.45 x 10^-2 m

A 44-kg child steps onto a scale and the scale reads 430 N. What is the magnitude of the normal force acting on the child?

430 N

At a playground, a child slides down a slide that makes a 42° angle with the horizontal direction. The coefficient of kinetic friction for the child sliding on the slide is 0.20. What is the magnitude of her acceleration during her sliding?

5.1 m/s2

A 20.0-kg package is dropped from a high tower in still air and is "tracked" by a radar system. When the package is 25 m above the ground, the radar tracking indicates that its acceleration is 7.0 m/s2. Determine the force of air resistance on the package.

626 N

Which one of the following choices is equivalent to 8.0m^2 ?

8.0 x 10^4 cm^2

A certain crane can provide a maximum lifting force of 25 000 N. It hoists a 2000-kg load starting at ground level by applying the maximum force for a 2-second interval; then, it applies just sufficient force to keep the load moving upward at constant speed. Approximately how long does it take to raise the load from ground level to a height of 30 m?

7 s

A Canadian goose flew 845 km from Southern California to Oregon with an average speed of 28.0 m/s. How long, in hours, did it take the goose to make this journey?

8.38 h

For which one of the following situations will the path length equal the magnitude of the displacement?

A ball is rolling down an inclined plane.

In which one of the following cases is the displacement of the object directly proportional to the elapsed time?

A ball rolls with constant velocity.

Which one of the following situations is not possible ?

A body travels with a constant velocity and a time-varying acceleration

Two forces act on a hockey puck. For which orientation of the forces will the puck acquire an acceleration with the largest magnitude?

Arrows pointing same way

Which one of the following is not a vector quantity ?

Average Speed

Which one of the following choices is a vector quantity ?

Displacement

Which one of the physical quantities listed below is not correctly paired with its SI unit and dimension ?

Displacement m/s^2 [L]/[T]^2

Which one of the following terms is used to indicate the natural tendency of an object to remain at rest or in motion at a constant speed along a straight line ?

Inertia

A small plane climbs with a constant velocity of 240 m/s at an angle of 24° with respect to the horizontal. Which statement is true concerning the magnitude of the net force on the plane?

It is equal to zero newtons.

Complete the following statement: An inertial reference frame is one in which

Newton's first law of motion is valid

A football is kicked at an angle theta with respect to the horizontal. Which one of the following statements best describes the acceleration of the football during this event if air resistance is neglected ?

The acceleration is 9.8 m/s^2 at all times

Two point masses m and M are separated by a distance d. If the distance between the masses is increased to 3d, how does the gravitational force between them change?

The force will be one-ninth as great.

A rock is suspended from a string moves downward at constant speed. Which statement is true concerning the tension in the string if air resistance is ignored ?

The tension is equal to the weight of the rock

A rock is suspended from a string; and it accelerated upward. Which statement is true concerning the tension in the string ?

The tension is greater than the weight of the rock.

A rock is suspended from a string; and it accelerated downward. Which one of the following statements concerning the tension in the string is true ?

The tension is less than the weight of the rock

Which one of the following statements concerning the two "gravitational constant" G, the universal gravitational constant, and g the magnitude of the acceleration due to gravity is true ?

The value of G is the same everywhere in the universe, but the value of g is not.

A baseball is hit upward and travels along a parabolic arc before it strikes the ground. Which one of the following statements is necessarily true ?

The x-component of the velocity of the ball is the same throughout the ball's flight

What is the minimum number of vectors with unequal magnitudes whose vector sum can be zero ?

Three

Which one of the following statements must be true if the expression is to be used ?

a is constant

A passenger at rest on a flatbed train car fires a bullet straight up. The event is viewed by observers at rest on the station platform as the train moves past the platform with constant velocity. What is the trajectory of the bullet as described by the observers on the platform?

a parabolic path

Two vectors and are added together to form a vector . The relationship between the magnitudes of the vectors is given by A + B = C. Which one of the following statements concerning these vectors is true?

and must point in the same direction.

A 4-kg block is connected by means of a massless rope to a 2-kg block as shown in the figure. Complete the following statement: If the 4-kg block is to begin sliding, the coefficient of static friction between the 4-kg block and the surface must be

less than 0.5, but greater than zero.

A bullet is aimed at a target on the wall a distance L away from the firing position. Because of gravity, the bullet strikes the wall a distance Δy below the mark as suggested in the figure.Note: The drawing is not to scale.If the distance L was half as large and the bullet had the same initial velocity, how would Δy be affected?

Δy will be one fourth as large.

A runaway dog walks 0.64 km due north. He then runs due west to a hot dog stand. If the magnitude of the dog's total displacement vector is 0.91 km, what is the magnitude of the dog's displacement vector in the due west direction?

0.65 km

A ball is thrown vertically upward from the surface of the earth. Consider the following quantities: (1) the speed of the ball; (2) the velocity of the ball; (3) the acceleration of the ball. Which is these is (are) zero when the ball has reached the maximum height ?

1 and 2 only

An arrow is shot horizontally from a height of 4.9 m above the ground. The initial speed of the arrow is 45 m/s. Neglecting friction, how long will it take the arrow to hit the ground?

1.0 s

The surface of a lake has an area of 15.5 km2. What is the area of the lake in m2?

1.55 × 107 m2

Two forces act on a 4.5-kg block resting on a frictionless surface as shown. What is the magnitude of the horizontal acceleration of the block?

1.8 m/s2

A net force of 25 N is applied for 5.7 s to a 12-kg box initially at rest. What is the speed of the box at the end of the 5.7-s interval?

12 m/s

A train travels due south at 60 m/s. It reverses its direction and travels due north at 60 m/s.What is the change in velocity of the train?

120 m/s, due north

The x and y components of a displacement vector are -3.00 m and +4.00 m, respectively. What angle does this vector make with the positive x axis?

127°

A cannonball at ground level is aimed 30.0° above the horizontal and is fired with an initial speed of 125 m/s. How far away from the cannon will the cannonball hit the ground?

1380 m

Three spring scales are attached along a straight line as shown. The scale on the left is attached to a wall. A force of 15 N is applied to the scale at the right.What is the reading on the middle scale?

15 N

Ryan throws a tennis ball vertically upward. The ball returns to the point of release after 3.5 s. What is the speed of the ball as it is released?

17 m/s

Water drips from rest from a leaf that is 15 meters above the ground. Neglecting air resistance, what is the speed of each water drop when it hits the ground?

17 m/s

A projectile is fired horizontally with an initial speed of 57 m/s. What are the horizontal and vertical components of its displacement 3.0 s after it is fired?horizontal vertical

170 m -44 m

What is the angle between the vectors and - when they are drawn from a common origin ?

180 Degrees

A cheetah is walking at a speed of 1.15 m/s when it observes a gazelle 43.0 m directly ahead. If the cheetah accelerates at 9.25 m/s2, how long does it take the cheetah to reach the gazelle if the gazelle doesn't move?

2.93 s

During the first 18 minutes of a 1.0-hour trip, a car has an average speed of 11 m/s. What must the average speed of the car be during the last 42 minutes of the trip be if the car is to have an average speed of 21 m/s for the entire trip?

25 m/s

Two cars A and B approach each other at an intersection. Car A is traveling south at 20 m/s, while car B is traveling east at 17 m/s. What is the velocity of car A as described by the passengers in car B?

26 m/s, 50° south of west

A bird flies 25.0 m in the direction 55° east of south to its nest on a cliff. The bird then flies 75.0 m in the direction 55° west of north to the top of a tree. What are the northward and westward components of the resultant displacement of the bird from its nest?northward westward

29 m 41 m

A 975-kg car accelerates from rest to 26.7 m/s in a distance of 120 m. What is the magnitude of the average net force acting on the car?

2900 N

A net force is required to give an object with mass m an acceleration a. If a net force 6 is applied to an object with mass 2m, what is the acceleration on this object ?

3

A 250-N force is directed horizontally as shown to push a 29-kg box up an inclined plane at a constant speed. Determine the magnitude of the normal force, FN, and the coefficient of kinetic friction, μk.

370 N 0.26

A ball is dropped from rest from a tower and strikes the ground 110 m below. Approximately how many seconds does it take the ball to strike the ground after being dropped? Neglect air resistance.

4,74 s

A body initially at rest is accelerated at a constant rate for 5.0 seconds in the positive x direction. If the final speed of the body is 20.0 m/s, what was the body's acceleration?

4.0 m/s2

A hammer is accidentally dropped from rest down a vertical mine shaft. How long does it take for the rock to reach a depth of 79 m? Neglect air resistance.

4.0 s

A rock is dropped from rest from a height h above the ground. It falls and hits the ground with a speed of 11 m/s. From what height should the rock be dropped so that its speed on hitting the ground is 22 m/s? Neglect air resistance.

4.0h

Two forces act on a 16-kg object. The first force has a magnitude of 68 N and is directed 24° north of east. The second force is 32 N, 48° north of west. What is the acceleration of the object resulting from the application of these two forces to the object?

4.1 m/s2, 52° north of east

A car travels along a highway with a velocity of 24 m/s, west. The car exits the highway; and 4.0 s later, its instantaneous velocity is 16 m/s, 45° north of west. What is the magnitude of the average acceleration of the car during the four-second interval?

4.5 m/s2

City A lies 30 km directly south of city B. A bus, beginning at city A travels 50 km at 37° north of east to reach city C. How far and in what direction must the bus go from city C to reach city B?

40 km, west

The Boston Marathon is the oldest annual foot race, in which those that finish complete a distance of 26 miles, 385 yards. Express this distance in kilometers.

42.186 km

On a two lane highway, a car is following a pickup truck. At one instant, the car has a speed of 32 m/s and is 184 m behind the truck. At the same time, the truck has a speed of 28 m/s. If neither vehicle accelerates, how long will it take the car to catch up to the truck?

46 s

A basketball is launched with an initial speed of 8.0 m/s and follows the trajectory shown. The ball enters the basket 0.96 s after it is launched. What are the distances x and y? Note: The drawing is not to scale.

5.4 m 0.91 m

A massless horizontal strut is attached to the wall at the hinge O. Which one of the following phrases best describes the force that the hinge pin applies to the strut if the weight of the cables is also neglected?

50 lb, to the right

A woman stands on a bathroom scale in an elevator that is not moving. The scale reads 500 N. The elevator then moves downward at a constant velocity of 5 m/s. What does the scale read while the elevator descends with constant velocity.

500 N

A woman stands on a bathroom scale in an elevator that is not moving. The scale reads 500 N. The elevator then moves downward at a constant velocity of 5 m/s. What does the scale read while the elevator descends with constant velocity?

500 N

A quarterback throws a pass at an angle of 35° above the horizontal with an initial speed of 25 m/s. The ball is caught by the receiver 2.55 seconds later. Determine the distance the ball was thrown.

52 m

A 20.0-kg package is dropped from a high tower in still air and is "tracked" by a radar system. When the package is 25 m above the ground, the radar tracking indicates that its acceleration is 7.0 m/s2. Determine the force of air resistance on the package.

56 N

A car traveling along a road begins accelerating with a constant acceleration of 1.5 m/s2 in the direction of motion. After traveling 392 m at this acceleration, its speed is 35 m/s. Determine the speed of the car when it began accelerating.

7.0 m/s

A displacement vector has a magnitude of 810 m and points at an angle of 18° above the positive x axis. What are the x and y scalar components of this vector? x scalar component y scalar component

770 m 250 m

A race car has a speed of 80 m/s when the driver releases a drag parachute. If the parachute causes a deceleration of -4 m/s2, how far will the car travel before it stops?

800 m

Ball A is dropped from rest from a window. At the same instant, ball B is thrown downward; and ball C is thrown upward from the same window. Which statement concerning the balls after their release is necessarily true if air resistance is neglected ?

All three balls have the same acceleration at any instant

The graph shows the velocities of two objects of equal mass as a function of time. Net forces FA, FB, and FC acted on the objects during intervals A, B, and C, respectively. Which one of the following choices is the correct relationship between the magnitudes of the net forces?

FA > FB = FC

A ball is thrown vertically upward from the surface of the earth. The ball rises to some maximum height and falls back toward the surface of the earth. Which one of the following statements concerning this situation is true if air resistance is neglected ?

The ball is freely falling body for the duration of its flight.

A 10-kg block is pushed against a vertical wall by a horizontal force of 100 N as shown in the figure. The coefficient of static friction, μs, between the block and the wall is 0.60; and the coefficient of kinetic friction, μ k, is 0.40. Which one of the following statements is true, if the block is initially at rest?

The block will slide down the wall because the force of static friction can be no larger than 60 N.

An object moving along a straight line is decelerating. Which one of the following statements concerning the object's acceleration is necessarily true ?

The direction of the acceleration is in the direction opposite to that of the velocity

A particle travels along a curved path between two points P and Q as shown. The displacement of the particle does not depend on

The distance traveled from P to Q

Which one of the following quantities is a vector quantity ?

The earth's pull on your body

An object moves due east at constant speed. A net force directed due north then acts on the object for 5.0 s. At the end of the 5.0-second period, the net force drops to zero newtons. Which one of the following statements is necessarily true?

The final velocity of the object is directed north of east.

Two point masses m and M are separated by a distance d. If the separation d remains fixed and the masses are increased to the values 3m and 3M respectively, how does the gravitational force between them change?

The force will be nine times as great.

Two satellites of different masses are in the same circular orbit around the earth. Which one of the following statements is true concerning the magnitude of the gravitational force that acts on each of them?

The magnitude of the gravitational force depends on their masses.

The figure shows the velocity versus time curve for a car traveling along a straight line.

The magnitude of the net force acting during interval A is less than that during C.

A rock is thrown straight up from the earth' surface. Which one the following statements concerning the net force acting on the rock at the top of its path is true ?

The net force is equal to the weight of the rock

Complete the following statement: The term net force most accurately describes

The quantity that changes the velocity of an object.

A rock is suspended from a string; and it moves downward at constant speed. Which one of the following statements is true concerning the tension in the string if air resistance is not ignored ?

The tension is less than the weight of the rock