SMDEP Physics Projectile motion Ch 3 28 1

SMDEP Physics Projectile motion

Ch. 3, #28 1. 2. 3. 4. 5. 6. 1/6 as far 6 times as far 3. 4 times as far Other Didn’t finish

Ch. 3, #32 1. 2. 3. 4. 5. 6. 12. 9 m 129 m 1. 29 m 38. 7 m Other Didn’t finish

Ch. 3, #37 1. 2. 3. 4. 5. 6. 32. 7 s 3. 27 s 5. 71 s 0 s Other Didn’t finish

Attendance: What’s your favorite type of music? 1. 2. 3. 4. 5. 6. 7. Jazz Classical Hip-hop Rock Techno Country American Idol

Survey: How much time are you spending on reading plus homework each day? 1. 2. 3. 4. 5. 6. 0 -1 hour 1 -2 hours 2 -3 hours 3 -4 hours 4 -5 hours More than 5 hours

The following graph shows position as a function of time for two trains running on parallel tracks. Which of the following is true? 1. 2. 3. 4. At time T both trains have the same velocity Both trains speed up all the time Both trains have the same velocity at some time before T Somewhere on the graph, both trains have the same acceleration

position Train 1 Train 2 T time

The following graph shows position as a function of time for two trains running on parallel tracks. Which of the following is true? 1. 2. 3. 4. At time T both trains have the same velocity Both trains speed up all the time Both trains have the same velocity at some time before T Somewhere on the graph, both trains have the same acceleration

For the same graph, compare the trains’ average velocities during the time interval between t=0 and t=T 1. 2. 3. <v 1> greater than <v 2> <v 1> less than <v 2> <v 1> equal to <v 2>

position Train 1 Train 2 T time

For the same graph, compare the trains’ average velocities during the time interval between t=0 and t=T 1. 2. 3. 0 of 70 <v 1> greater than <v 2> <v 1> less than <v 2> <v 1> equal to <v 2> 10

The following graph shows the velocity of three objects during the time interval from t 1 to t 2. All three have the same initial and final velocities. Which object has the greatest velocity over the entire interval? 1. 2. 3. 4. 1 2 3 All three have the same average velocity. 5. Cannot tell without knowing the starting positions.

velocity 1 2 3 t 1 t 2 time

The following graph shows the velocity of three objects during the time interval from t 1 to t 2. All three have the same initial and final velocities. Which object has the greatest velocity over the entire interval? 1. 2. 3. 4. 1 2 3 All three have the same average velocity. 5. Cannot tell without knowing the starting 0 of positions. 70 10

A stone is launched vertically up, and its speed slows under the influence of gravity. Suppose we film this motion and play the tape backward (so the tape begins with the ball at a high point and ends with the ball at a low point). 1. 2. 3. 0 of 70 What you see on the tape could never happen in reality The tape shows the motion of a stone in free fall but the acceleration is upward rather than downward. The tape shows the motion of a stone in free fall with downward acceleration g. 10

70 A ball is dropped from a cliff (from rest). A second ball is thrown upward from the cliff, and eventually falls back to where the first ball hit. 1. Both balls have the same speed when they pass the cliff. Both balls hit the ground below with the same velocity. Both balls have the same acceleration. Both balls take the same time to fall starting from when they pass the cliff. 2. 3. 4. 0 VOTE

A person standing at the edge of a cliff throws one ball straight up and another straight down at the same initial speed. Neglecting air resistance, which ball hits the ground with greater speed? 1. 2. 3. 4. The one thrown upward. The one thrown downward. Neither – they hit with the same speed. Not enough information to tell. 0 of 70 10

A bowling ball is dropped from a building at the same time that a stone is launched upward from the ground. The initial speed of the stone is equal to the speed of the ball just before it hits the ground. The ball and stone cross: 1. Above 2. Exactly at 3. Below . . half the height of the building. 0 of 70 10

An astronaut stands on the moon where the local acceleration due to gravity, g. Moon is 1/6 the value on Earth, g. Earth = 9. 8 m/s 2. If the astronaut drops a golf ball from a certain height, the time it takes to hit the ground 1. 2. 3. 0 of 70 Is greater than Is equal to Is less than the time it takes a golf ball on Earth to fall the same distance. : 10

Consider the following displacement: r = 6 t i + 4 j 10 t 2 k In what direction is the acceleration? 1. + k 2. - k 3. In the direction of the vector 6 i 20 k 4. Can’t tell without a lot of algebra 5. Can’t say without specifying the time 0 of 70 10 Seconds Remaining

Consider the following four situations: 1. You make a U-turn at constant speed 2. You drive forward, stop, then go in reverse 3. You make a right turn at constant speed 4. You make a right turn and brake while turning For which of these situations do you experience nonzero average acceleration? 0 of 70 1. 2. 3. 4. 5. 4 2 and 4 2 1, 2, and 4 All of them 10

Q. Two velocities with magnitudes 3. 0 m/s and 4. 0 m/s are added. Which of the following could NOT be the magnitude of their resultant velocity? 10 1. 2. 3. 4. 3. 5 m/s 5. 0 m/s 6. 6 m/s 7. 3 m/s 0 of 70

What is the minimum number of forces of equal magnitude that, when added, yield a vector sum of zero? 1. 2. 3. 4. 5. 0 of 70 Five Four Three Two One 10

What is the minimum number of forces of unequal magnitude that, when added, yield a vector sum of zero? 1. 2. 3. 4. 5. Five Four Three Two One 5 10 0 0

Two penguins are sliding on adjacent paths along the horizontal surface of an iceberg. One moves twice as fast as the other, and they both pass over the edge at the same instant. Which penguin hits the water first? 1. The penguin with the faster initial horizontal velocity. 2. The slower penguin. 70 3. They hit the water at the same time. 0 0 10

Where do the penguins land relative to each other? 70 1. 2. 3. 0 They land in nearly the same spot because the initial velocity on the iceberg doesn’t affect the subsequent motion. The faster penguin travels further from the iceberg. The slower penguin travels further from the iceberg because it takes longer to fall. 10