Exam 2: Motion in One Dimension

The captain orders his starship to accelerate from rest at a rate of "1 g" (1 g = 9.8 m/s²). How many days does it take the starship to reach 10% the speed of light? (Light travels at 3.0 × 10⁸ m/s.)

The slope of a position versus time graph gives

Suppose that a car traveling to the east (+x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration must be correct?

An object is moving with constant non-zero velocity in the +x direction. The position versus time graph of this object is

Under what condition is average velocity equal to the average of the object's initial and final velocity?

A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. What was the average speed of the runner in m/s?

The area under a curve in a velocity versus time graph gives

An object is moving in a straight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this time?

Abby throws a ball straight up and times it. She sees that the ball goes by the top of a flagpole after 0.50 s and reaches the level of the top of the pole after a total elapsed time of 4.1 s. What was the speed of the ball at launch? Neglect air resistance.

The figure shows the velocity-versus-time graph for a basketball player traveling up and down the court in a straight-line path. Find the displacement of the player (a) during the first two seconds. (b) between t = 4 s and t = 8 s.

A ball is projected upward at time t = 0 s, from a point on a flat roof 90 m above the ground. The ball rises and then falls with insignificant air resistance, missing the roof, and strikes the ground. The initial velocity of the ball is $80.5 \mathrm{~m} / \mathrm{s}$ Consider all quantities as positive in the upward direction. The vertical velocity of the ball when it is $89 \mathrm{~m}$ above the ground is closest to

If a car accelerates at a uniform 4.0 m/s², how long will it take to reach a speed of 80 km/hr, starting from rest?

The figure shows a graph of the position x of two cars, C and D, as a function of time t. According to this graph, which statements about these cars must be true? (There could be more than one correct choice.)

You are driving home on a weekend from school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your hometown from school?

If you run a complete loop around an outdoor track of length 400 m in 100 s, find your (a) average velocity and (b) average speed.

A runner runs around a track consisting of two parallel lines 96 m long connected at the ends by two semicircles with a radius of 49 m. She completes one lap in 100 seconds. What is her average speed?

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? Neglect air resistance.

A rock from a volcanic eruption is launched straight up into the air with no appreciable air resistance. Which one of the following statements about this rock while it is in the air is correct?

A ball is projected upward at time t = 0 s, from a point on a flat roof 10 m above the ground. The ball rises and then falls with insignificant air resistance, missing the roof, and strikes the ground. The initial velocity of the ball is $58.5 \mathrm{~m} / \mathrm{s} .$ Consider all quantities as positive in the upward direction. At time $t=5.97 \mathrm{~s}$ , the vertical velocity of the ball is closest to

An object is dropped from a bridge. A second object is thrown downwards 1.0 s later. They both reach the water 20 m below at the same instant. What was the initial speed of the second object? Neglect air resistance.