chapter 2 physics

Which of the following five coordinate versus time graphs represents the motion of an object moving with a constant speed?

(xt)

Its coordinate in meters is given by x(t) = 75t - 1.0t3, where t is in seconds. When it momentarily stops its acceleration is:

) -30 m/s2

The coordinate of an object is given as a function of time by x = 7t - 3t2, where x is in meters and t is in seconds. Its average velocity over the interval from t = 0 to t = 2 s is:

) -5 m/s

. An object is thrown straight down with an initial speed of 4 m/s from a window which is 8 m above the ground. The time it takes the object to reach the ground is:

) 0.93 s

Two automobiles are 150 kilometers apart and traveling toward each other. One automobile is moving at 60 km/h and the other is moving at 40 km/h. In how many hours will they meet

) 1.5

One object is thrown vertically upward with an initial velocity of 100 m/s and another object with an initial velocity of 10 m/s. The maximum height reached by the first object will be _______ that of the other.

) 100 times

At a location where g = 9.80 m/s2, an object is thrown vertically down with an initial speed of 1.00 m/s. After 5.00 s the object will have traveled:

) 127.5 m

. A car, initially at rest, travels 20 m in 4 s along a straight line with constant acceleration. The acceleration of the car is

) 2.5 m/s2

Over a short interval, starting at time t = 0, the coordinate of an automobile in meters is given by

) 27 m/s; 0

A heavy ball falls freely, starting from rest. Between the third and fourth second of time it travels a distance of

) 34.3 m

. A baseball is hit straight up and is caught by the catcher 2.0 s later. The maximum height of the ball during this interval is:

) 4.9 m

constant speed

) I and IV only linear increases xt flat line vt

An object is thrown straight up from ground level with a speed of 50 m/s. If g = 10 m/s2 its distance above ground level 1.0 second later is:

) 45 m

Their coordinates (in meters) as functions of time (in seconds) are given by particle 1: x(t) = 3.5 - 2.7t3 particle 2: x(t) = 3.5 + 2.7t3 particle 3: x(t) = 3.5 + 2.7t2 particle 4: x(t) = 3.5 - 3.4t - 2.7t2

) All four

y = at - bt2. The dimensions of the quantities a and b are respectively: A) L2/T, L3/T2

) L/T, L/T2

. A feather, initially at rest, is released in a vacuum 12 m above the surface of the Earth. Which of the following statements is correct?

) The acceleration of the feather remains constant during the fall

Over a short interval near time t = 0 the coordinate of an automobile in meters is given by x(t) = 27t - 4.0t3, where t is in seconds. At the end of 1.0 s the acceleration of the auto is:

-24 m/s2

A baseball is hit straight up and is caught by the catcher 2.0 s later. The maximum height of the ball during this interval is:

4.9 m

. A stone is released from rest from the edge of a building roof 190 m above the ground. Neglecting air resistance, the speed of the stone, just before striking the ground, is: A) 43 m/s

61 m/s

A particle moves along the x axis from xi to x f . Of the following values of the initial and final coordiantes, which results in a negative displacement?

xi = -4m, x f = -8m

Which one of the following statements is correct for an object released from rest

) The average velocity during the first second of time is 4.9 m/s

. The diagram represents the straight line motion of a car. Which of the following statements is true?

) The car accelerates at 6 m/s2 for the first 2 s

The coordinate-time graph of an object is a straight line with a positive slope. The object has

) constant velocity

A baseball is thrown vertically into the air. The acceleration of the ball at its highest point is

) g, down

An object is thrown vertically upward with a certain initial velocity in a world where the acceleration due to gravity is 19.6 m/s2. The height to which it rises is ____ that to which the object would rise if thrown upward with the same initial velocity on the Earth. Neglect friction.

) half

. An object is shot vertically upward. While it is rising

) its velocity is upward and its acceleration is downward

A freely falling body has a constant acceleration of 9.8 m/s2. This means that:

) the speed of the body increases by 9.8 m/s during each second

time by x = 4t2 - 3t3, where x is in meters and t is in seconds. Its average acceleration over the interval from t = 0 to t = 2 s is:

-10 m/s2

A car starts from Hither, goes 50 km in a straight line to Yon, immediately turns around, and returns to Hither. The time for this round trip is 2 hours. The magnitude of the average velocity of the car for this round trip is:

0

The coordinate of a particle in meters is given by x(t) = 16t - 3.0t3, where the time t is in seconds. The particle is momentarily at rest at t =

1.3 s

. At a stop light, a truck traveling at 15 m/s passes a car as it starts from rest. The truck travels at constant velocity and the car accelerates at 3 m/s2. How much time does the car take to catch up to the truck?

10 s

An object is released from rest.How far does it fall during the second second of its fall?

15 m

An object is thrown vertically upward at 35 m/s. Taking g = 10 m/s2, the velocity of the object 5 seconds later is:

15 m/s down

A stone is thrown vertically upward with an initial speed of 19.5 m/s. It will rise to a maximum height of:

19.4 m

. A stone is released from a balloon that is descending at a constant speed of 10 m/s. Neglecting air resistance, after 20 s the speed of the stone is

206 m/s

A car starts from rest and goes down a slope with a constant acceleration of 5 m/s2. After 5 seconds the car reaches the bottom of the hill. Its speed at the bottom of the hill, in meters per second, is

25

The graph represents the straight line motion of a car. How far does the car travel between t = 2 seconds and t = 5 seconds

36 m (hill like graph)

A ball rolls up a slope. At the end of three seconds its velocity is 20 cm/s; at the end of eight seconds its velocity is 0. What is the average acceleration from the third to the eighth second?

4.0 cm/s2

A racing car traveling with constant acceleration increases its speed from 10 m/s to 30 m/s over a distance of 60 m? How long does this take? A) 2.0 s

4.0 s

. A projectile is shot vertically upward with a given initial velocity. It reaches a maximum height of 100 m. If, on a second shot, the initial velocity is doubled then the projectile will reach a maximum height of:

400 m

How far does a car travel in 6 s if its initial velocity is 2 m/s and its acceleration is 2 m/s2 in the forward direction?

48 m

Starting at time t = 0, an object moves along a straight line with velocity in m/s given by v(t) = 98 - 2t2, where t is in seconds. When it momentarily stops its acceleration is:

49 m/s2

. A car starts from Hither, goes 50 km in a straight line to Yon, immediately turns around, and returns to Hither. The time for this round trip is 2 hours. The average speed of the car for this round trip is

50 km/h

A car travels 40 kilometers at an average speed of 80 km/h and then travels 40 kilometers at an average speed of 40 km/h. The average speed of the car for this 80 km trip is:

53 km/h

initial velocity of 12 m/s west experiences a constant acceleration of 4 m/s2 west for 3 seconds. During this time the object travels a distance of

54 m

. An object starts from rest at the origin and moves along the x axis with a constant acceleration of 4 m/s2. Its average velocity as it goes from x = 2 m to x = 8 m is:

6 m/s

Neglecting the effect of air resistance a stone dropped off a 175-m high building lands on the ground in:

6 s

A car moving with an initial velocity of 25 m/s north has a constant acceleration of 3 m/s2 south. After 6 seconds its velocity will be:

7 m/s north

. An object dropped from a window of a tall building hits the ground in 12.0 s. If its acceleration is 9.80 m/s2, the height of the window above the ground is:

706 m

As a rocket is accelerating vertically upward at 9.8 m/s2 near the Earth's surface, it releases a projectile. Immediately after release the acceleration (in m/s2) of the projectile is:

9.8 down

Of the following situations, which one is impossible?

A body having constant velocity and variable acceleration

49. The acceleration of an object, starting from rest, is shown in the graph below. Other than at t = 0, when is the velocity of the object equal to zero?

At no other time less than or equal to 5 s.

An elevator is moving upward with constant acceleration. The dashed curve shows the position y of the ceiling of the elevator as a function of the time t. At the instant indicated by the dot, a bolt breaks loose and drops from the ceiling. Which curve best represents the position of the bolt as a function of time

B

particle 1: x(t) = 3.5 - 2.7t3 particle 2: x(t) = 3.5 + 2.7t3 particle 3: x(t) = 3.5 + 2.7t2 particle 4: x(t) = 3.5 - 3.4t - 2.7t2 Which of these particles have constant acceleration?

Only 3 and 4

A drag racing car starts from rest at t = 0 and moves along a straight line with velocity given by v = bt2, where b is a constant. The expression for the distance traveled by this car from its position at t = 0 is:

bt3/3

The area under a velocity-time graph represents

displacement

. A ball is in free fall. Its acceleration is

downward during both ascent and descent

A car accelerates from rest on a straight road. A short time later, the car decelerates to a stop and then returns to its original position in a similar manner, by speeding up and then slowing to a stop. Which of the following five coordinate versus time graphs best describes the motion?

e parabola

The velocity of an object is given as a function of time by v = 4t - 3t2, where v is in m/s and t is in seconds. Its average velocity over the interval from t = 0 to t = 2 s:

is 0

The diagram shows a velocity-time graph for a car moving in a straight line. At point P the car must be

moving at about 45 with respect to the x axis (P almost in the middle)

Throughout a time interval, while the speed of a particle increases as it moves along the x axis, its velocity and acceleration might be:

negative and negative, respectively

A particle moves along the x axis according to the equation x = 6t2 where x is in meters and t is in seconds. Therefore:

none of the above

. A particle moves on the x axis. When its acceleration is positive and increasing

none of the above must be true

An object is thrown straight up from ground level with a speed of 50 m/s. If g = 10 m/s2 its distance above ground level 6.0 s later is

none of these

Which of the following five acceleration versus time graphs is correct for an object moving in a straight line at a constant velocity of 20 m/s?

nothing (derivative of constant is zero)

. A ball is in free fall. Upward is taken to be the positive direction. The displacement of the ball is

positive during ascent and negative during descent

. An object is dropped from rest. Which of the five following graphs correctly represents its motion? The positive direction is taken to be downward

slope type graph vt

A stone is dropped from a cliff. The graph (carefully note the axes) that best represents its motion while it falls is

slope type vt

An object has a constant acceleration of 3 m/s2. The displacement versus time graph for this object has a slope:

that increases with time

Displacement can be obtained from:

the area under a velocity-time graph

The average speed of a moving object during a given interval of time is always:

the distance covered during the time interval divided by the time interval

The diagram shows a velocity-time graph for a car moving in a straight line. At point Q the car must be

traveling in the reverse direction to that at point P (q is down)

. Which of the following five coordinate versus time graphs represents the motion of an object whose speed is increasing

upward curve

An object is thrown vertically into the air. Which of the following five graphs represents the velocity (v) of the object as a function of the time (t)? The positive direction is taken to be upward

vt slope downward

A particle moves along the x axis from xi to x f . Of the following values of the initial and final coordinates, which results in the displacement with the largest magnitude?

xi = -4m, x f = 4m

Which of the following five coordinate versus time graphs represents the motion of an object whose speed is increasing?

xt