Test 1 Review

f = mg sinθ.

27) In Fig. 5-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The force of static friction f must be such that A) f = mg cosθ. B) f > mg sinθ. C) f = mg sinθ. D) f > mg. E) f > mg cosθ

84.1 N

A 4.00-kg block rests on a 30.0 degree incline as shown in Fig. 5-5. If the coefficient of static friction between the block and the incline is 0.700, with what magnitude force must a horizontal force act on the block to start it moving up the incline? A) 51.1 N B) 76.4 N C) 34.0 N D) 84.1 N E) 54.7 N

equal to its weight

A ball is thrown up into the air. Ignore air resistance. When it is rising and reaches half of its maximum height, the net force acting on it is A) less than its weight, but not zero N. B) equal to its weight. C) greater than its weight. D) zero N. E) Cannot be determined without additional information.

Mg cos θ

A block of mass M slides down a frictionless plane inclined at an angle θ with the horizontal. The normal reaction force exerted by the plane on the block is A) Mg tan θ. B) Mg. C) Mg cos θ. D) Mg sin θ. E) zero, since the plane is frictionless.

5.4 m

A boy throws a ball with an initial velocity of 25 m/s at an angle of 30° above the horizontal. How high above the projection point is the ball after 2.0 s? A) 50 m B) 5.4 m C) 43 m D) 25 m E) 13 m

4.0 m/s2

A force of 120 N is applied to an object whose mass is 30 kg. The objectʹs acceleration is A) 2.0 m/s2. B) 4.0 m/s2. C) 150 m/s2. D) 0.25 m/s2. E) 3600 m/s2.

is (EXACTLY 2400)

A golf club hits a golf ball w/ a force of 2400 N. The golf ball hits the club w/ a force _________ A) slightly more than 2400 N. B) slightly less than 2400 N. C) exactly 2400 N. D) close to 0 N.

9.4 m

A jumper in the long-jump goes into the jump with a speed of 12 m/s at an angle of 20 ° above the horizontal. How far does the jumper jump? A) 3.4 m B) 15 m C) 18 m D) 6.2 m E) 9.4 m

60,000 N

A locomotive is pulling three wagons along a level track with a force of 100,000 N. The wagon next to the locomotive has a mass of 80,000 kg, the next one, 50,000 kg, and the last one, 70,000 kg. Neglect friction. What is the force between the 80,000-kg and 50,000-kg wagons? A) 50,000 N B) 65,000 N C) 35,000 N D) 40,000 N E) 60,000 N

0 m/s^2

A projectile is launched with an initial velocity of 80 m/s at an angle of 30° above the horizontal. Neglecting air resistance, what is horizontal component of the projectileʹs acceleration? A) 0 m/s2 B) 80 m/s2 C) 9.8 m/s2 D) 40 m/s2 E) 4.9 m/s2

It is equal to its initial horizontal velocity.

A rock is thrown at some angle above the horizontal with a certain velocity. It reaches its highest point and starts falling down. What is the velocity of the rock at the highest point of its trajectory? A) It is equal to its initial horizontal velocity. B) 9.8 m/s C) 0 D) It is equal to its initial velocity. E) It is equal to its initial vertical velocity.

it is equal to the magnitude of its initial velocity

A rock is thrown from ground level at some angle above the horizontal with a certain velocity. It reaches its highest point and starts falling down. What is the magnitude of the velocity of the rock right before it hits the ground? A) It is equal to its initial vertical velocity. B) It is equal to its initial horizontal velocity. C) It is equal to the magnitude of its initial velocity. D) 0 E) Cannot be determined without additional information

a quantity that is specified by a numerical value only.

A scalar quantity is defined as A) a quantity that is specified by using both a numerical value and a direction. B) a quantity that is specified by a numerical value only.

6000

A truck is towing a car whose mass is one quarter that of the truck. The force exerted by the truck on the car is 6000 N. The force exerted by the car on the truck is A) 1500 N. B) 12000 N. C) 6000 N. D) 24000 N. E) 3000 N

1*10^-6

A typical E.coli bacterium is measured in microns. Which represents a micron? A) 1 × 10-15 B) 1 × 10-3 C) 1 × 10-6 D) 1 × 10-12 E) 1 × 10-9

5,350 square meters

An American football field, including end zones, is 360 feet long and 160 feet wide. What is its area in square meters? A) 12,100 square meters B) 4,920 square meters C) 88.0 square meters D) 13,200 square meters E) 5,350 square meters

93.0 m/s

An airplane starts from rest and accelerates at 10.8 m/ s2. What is its speed at the end of a 400 m-long runway? A) 93.0 m/s B) 186 m/s C) 4320 m/s D) 37.0 m/s E) 65.7 m/s

arccos (1/3)= 70.5

An ant walks down the surface of a ball. If the ant begins to slip when the normal force is less than one-third of the antʹs weight, at what angle, measured from the top of the ball, does the ant begin to slip? A) 70.5° B) 19.5° C) 35.2° D) 55.0° E) 18.4°

600 N

An astronaut weighs 99.0 N on the Moon, where the acceleration of gravity is 1.62 m/ s2. How much does she weigh on Earth? A) 440 N B) 600 N C) 61.0 N D) 16.2 N E) 99.0 N

600 N

An astronaut weighs 99.0 N on the Moon, where the acceleration of gravity is 1.62 m/ s2. How much does she weigh on Earth? A) 440 N B) 99.0 N C) 61.0 N D) 16.2 N E) 600 N

a parabolic curve.

An object is moving with constant non-zero acceleration in the +x-axis. The position versus time graph of this object is A) a parabolic curve. B) a horizontal straight line. C) a vertical straight line. D) a straight line making an angle with the time axis. E) a hyperbolic curve.

The net force on the object is zero.

An object is moving with constant velocity. Which of the following statements is true? A) A constant force is being applied in the direction opposite of motion. B) There is no frictional force acting on the object. C) A constant force is being applied in the direction of motion. D) There are no forces acting on the object. E) The net force on the object is zero

0.52 s

An object is thrown upwards with a speed of 16 m/s. How long does it take it to reach a height of 7.0 m on the way up? A) 4.2 s B) 3.1 s C) 2.4 s D) 0.52 s E) 1.2 s

decrease

An object rests on an inclined surface. If the inclination of the surface is made steeper, what does the normal force on the object do? A) decrease B) stays the same C) increase D) The normal force is zero N. E) Cannot be determined without additional information

the velocity is not changing at that instant.

At a given instant, the acceleration of a certain particle is zero. This means that A) the velocity is not changing at that instant. B) the velocity is decreasing. C) the velocity is constant. D) the velocity is increasing. E) the velocity is zero.

Remains a non-zero constant

For general projectile motion, the vertical component of a projectileʹs acceleration A) continuously decreases. B) is zero. C) continuously increases. D) remains a non-zero constant. E) any of the above, depending on position.

C

Four students measure the mass of an object, each using a different scale. They record their results as follows: Student A B C D E Mass (g) 49.06 49 50 49.1 49.061 Which student used the least precise scale? A) A B) B C) C D) D E) E

the object is slowing down

If the acceleration vector of an object is directed anti-parallel to the velocity vector, then A) the object is turning. B) the object is slowing down. C) the object is speeding up. D) the object is moving with a constant velocity. E) the object is at rest.

the object is speeding up

If the acceleration vector of an object is directed parallel to the velocity vector, then A) the object is moving with a constant velocity. B) the object is speeding up. C) the object is at rest. D) the object is turning. E) the object is slowing down.

Its range will quadruple

If the initial speed of a projectile is doubled. A) Its range will double. B) Its range will quadruple. C) Its range will decrease by a factor of four. D) Its range will be increased by 1.41. E) Its range will be decreased by a factor of two.

EXACTLY 9.81

In Fig. 4-1 the scale at left is attached to the ceiling and a mass of 1.00 kg hangs from it. It reads 9.81 N. The identical scale at the right is connected by perfect strings passing over perfect pulleys to two 1.00 kg masses hanging vertically at the end of the strings. The scale at right reads A) more than 9.81 N, but not quite twice as much. B) exactly 19.62 N. C) more than 19.62 N. D) less than 9.81 N. E) exactly 9.81 N.

move with constant velocity

In the absence of an external force, a moving object will A) slow down and eventually come to a stop. B) move faster and faster. C) stop immediately. D) move with constant velocity. E) move with constant velocity for a while and then slow to a stop

280

In the year 2000, the average size of a transistor in a microprocessor was 250 nanometers. A human hair has a diameter of 70 microns (micrometers). How many transistors fit across a human hair? A) 280 B) 0.28 C) 28 D) 2800 E) 2.8

10.5 km

Refer to Figure 2-6. If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the distance you have traveled? A) 1.5 km B) 0 km C) 6.5 km D) 2.5 km E) 10.5 km

Ax = A cos 0° Bx = -B cos 60° Ay = A cos 90° By = B cos 30°.

Refer to Figure 3-1. The components of vectors A and B are A) Ax = A sin 90° Bx = B cos 60° Ay = A cos 90° By = B sin 60°. B) Ax = 0 Bx = B sin 30° Ay = 0 By = B cos 30°. C) Ax = A cos 90° Bx = B sin 60° Ay = A sin 90° By = B cos 60°. D) Ax = A cos 90° Bx = 0 Ay = A sin 90° By = 0 E) Ax = A cos 0° Bx = -B cos 60° Ay = A cos 90° By = B cos 30°.

M + N

Refer to Figure 3-2. Vector T as expressed in terms of vectors M and N is given by A) M. B) N . C) M + N . D) M - N . E) None of the other choices is correct.

displacement

The area under a curve in a velocity versus time graph gives A) acceleration. B) speed. C) displacement. D) velocity. E) distance traveled.

D) [M][L]-3.

The density of a solid object is defined as the ratio of the mass of the object to its volume. The dimension of density is A) [L]3/[M]. B) [M][L]. C) [M][L][T]. D) [M][L]-3. E) [M]/[L]

A= Distance B= Distance/time C= distance/time^2

The position, x, of an object is given by the equation x=A+Bt+Ct^2, where t=time. What are the dimensions of A, B, and C? A) distance, time, time B) distance/time, distance/time2, distance/time3 C) distance, distance, distance D) distance, distance/time, distance/time2 E) distance, time, time2

The time that it takes the radiation from a cesium-133 atom to complete 9,192,631,770 cycles of oscillation.

The second is currently defined as A) 1/86,400 of a mean solar day. B) the time required for light to travel 1/299,792,458 of a meter. C) the time that it takes the radiation from a Cesium-133 atom to complete 9,192,631,770 cycles of oscillation. D) 1/31,557,600 of the period of the Earthʹs rotation around the Sun. E) 1/86,164 of a sidereal day.

average velocity

The slope of a line connecting 2 points on a position vs time graph gives ______________ A) average acceleration. B) displacement. C) instantaneous velocity. D) instantaneous acceleration. E) average velocity.

0 degree

The sum of two vectors has the greatest magnitude when the angle between these two vectors is A) 0°. B) 90°. C) 180°. D) 270°. E) 60

four times long

Two athletes jump straight up. John has twice the initial speed of Harry. Compared to Harry, John jumps A) 1.41 times as long. B) twice as long. C) 0.50 times as long. D) four times as long. E) three times as long

the component of the force exerted by a surface perpendicular to the surface

What does the word ʺnormalʺ mean in the phrase ʺnormal forceʺ? A) the total force exerted by a surface B) the component of the force exerted by a surface parallel to the surface C) the force that is usually exerted by a surface D) the force is due to contact between two objects. E) the component of the force exerted by a surface perpendicular to the surface

21.9

What is the product of 11.24 and 1.95 ? A) 22 B) 21.9 C) 21.92 D) 21.918 E) 21.9180

It is less than its initial speed.

When a football in a field goal attempt reaches its maximum height, how does its speed compare to its initial speed? A) It is less than its initial speed. B) It is equal to its initial speed. C) It is zero. D) It is greater than its initial speed. E) Cannot be determined without additional information.

Kilogram

if you are measuring the mass of an elephant, the most appropriate SI unit is the A) kilogram B) gram. C) teragram. D) milligram. E) microgram.

180 degrees

what is the angle b/n the vectors A and -A when these vectors are drawn from a common origin? A) 360° B) 90° C) 0° D) 180° E) 270°