Chapter 3 A.P Physics Test

a ball is thrown with a velocity of 20m s at an angle of 60 above the horizontal. if we can neglect air resistance what is the horizontal component of its instantaneous velocity at the exact top of its trajectory

10 m/s

an athlete competing in the long jump leaves the ground with a speed of 9.14 m/s at an angle of 55 with the vertical. what is the length of the athletes jump if air resistance is of no significance

?

A boulder rolls off of a very high cliff and experiences no significant air resistance. While it is falling, its trajectory is never truly vertical. A. True B. False

A. True

Two golf balls are released at the same height. One ball is dropped vertically while the other is projected horizontally. The height of the two balls is always the same A. True B. False

A.True

Mary and Debra stand on a snow-covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30° below the horizontal; Debra throws her snowball upward, at 30° above the horizontal. Which of the following statements are true about just as the snowballs reach the ground below? (There could be more than one correct choice.) A. Mary's snowball will have a higher speed than Debra's snowball B. Mary's snowball reaches the ground before Debra's snowball. C. Debra's snowball will have a higher speed than Mary's snowball D. Both snowballs will hit the ground with the same speed E. Both snowball hit the ground at the same time

B. Mary's snowball reaches the ground before Debra's snowball. D. Both snowballs will hit the ground with the same speed

A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will A. be behind the package B. be directly over the package C. be in front of the package D. depend on the speed of the plane when the package was released

B. be directly over the package

A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory A. both the velocity and the acceleration of the soccer ball are zero B. neither the ball's velocity nor its acceleration are zero C. the ball's acceleration is zero but its velocity is not zero D. the ball's acceleration points upward E.the ball's velocity points downward

B. neither the ball's velocity nor its acceleration are zero

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity A. remains zero B. remains a non-zero constant C. continuously increases D.continuously decreases E. first decreases then increases

B. remains a non-zero constant

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there is no air resistance. A. James reaches the surface of the lake first B. John reaches the surface of the lake first C. James and John will reach the surface of the lake at the same time. D. Cannot be determined without knowing the mass of both James and John E. Cannot be determined without knowing the weight of both James and John

C. James and John will reach the surface of the lake at the same time.

In an air-free chamber, a pebble is thrown horizontally, and at the same instant a second pebble is dropped from the same height. Compare the times of fall of the two pebbles. A. The thrown pebble hits first B.The dropped pebble hits first C.They hit at the same time D.We cannot tell without knowing which pebble is heavier

C.They hit at the same time

The acceleration due to gravity on the Moon is only one-sixth of that on Earth, and the Moon has no atmosphere. If you hit a baseball on the Moon with the same effort ( and therefore at the speed and angle) as on Earth, how far would the ball travel on the Moon compared to on Earth? Neglecting air resistance on Earth. A. 1/6 as far as on Earth B. 36 times as far as on Earth C. the same distance as on Earth D. 6 times as far as on Earth E. √6 as far as on Earth

D. 6 times as far as on Earth

A projectile is fired from ground level on a horizontal plane. If the initial speed of the projectile is now doubled, and we neglect air resistance. A. its range will be increased by √2 B. its range will double C. its range will be decreased by a factor of two D. its range will quadruple E. its range will decrease by a factor of four

D. its range will quadruple

Which of the following statements are true about an object in two dimensional projectile motion with no air resistance? A.The speed of the object is constant but its velocity is not constant B. The acceleration of the object is +g when the object is rising and -g when it is falling C. The acceleration of the object is zero at its highest point. D.The speed of the object is zero at its highest point E.The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward.

E.The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward.