Chp. 4 Midterm Review Flashcards
The magnitude of the resultant of two vectors cannot be less than the magnitude of either of those two vectors.
False
If three vectors add to zero, they must all have equal magnitudes.
False
For general projectile motion with no air resistance, the horizontal component of a projectile’s velocity
Remains a non zero constant
For general projectile motion with no air resistance, the horizontal component of a projectile’s acceleration
Is always zero
For general projectile motion with no air resistance, the vertical component of a projectile’s acceleration
Remains a non zero constant
Which of the following statements are true about an object in two-dimensional projectile motion with no air resistance? (There could be more than one correct choice.)
The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward.
A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. Which object is traveling faster when it hits the level ground below if neither of them experiences any air resistance?
The ball
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
They hit at the same time
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
Be directly over the package
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.
James and John will reach the surface of the lake at the same time.
A rock is thrown from the upper edge of a tall cliff at some angle above the horizontal. It reaches its highest point and starts falling down. Which of the following statements about the rock’s motion are true just before it hits the ground? (There could be more than one correct choice.)
Its horizontal velocity component is the same as it was just as it was launched.
