Freefall
This term refers to a projectile that is only under the influence of the force of gravity and air resistance
What is freefall?
If an object traveled 5300 meters in 15 seconds, was its average velocity?
353 m/s
Name 3 things in physics that are vectors that we have discussed so far this year
What are displacement, velocity, acceleration, or force
A cannonball is launched from the ground 50 m/s at 15 degrees to the horizontal. What is its total hang time?
2.6 seconds
An object is dropped from rest. How fast is it going in 4 seconds?
40 m/s
The position of an object is given by the equation x = 3.0 t2 + 1.5 t + 4.5, where x is in meters and t is in seconds. What is the instantaneous acceleration of the object at t = 3.0 s?
6 m/s/s
You walk 20 meters West and then 10 meters south. What is the total displacment.
22.36 m SW
A plane is moving horizontally through the sky with speed v. A package is dropped from the plane and travels a horizontal distance h from the point of release to where it lands on a target. (see smartboard slide) If air resistance is negligible, the height from which the package is released is
1/2 g * (x/v)2
Abe Lincoln threw his 2kg mug straight up into the air with an initial velocity of 24 m/s. How fast is it traveling, and in which direction, 6 seconds later?
6 m/s, downward
A cart is moving in the +x-direction and passes the origin when time t=0. The cart then moves with decreasing speed, stops, and moves in the –x-direction with increasing speed. Sketch the graph that best represents the cart's position x as a function of time?
see smartboard slide
A vector B = 3i - 3j has a magnitude of
sqrt(18) OR 4.24
A spring-loaded gun can fire a projectile to a height h if it is fired straight up. If the same gun is pointed at an angle of 45° from the vertical, what maximum height can now be reached by the projectile?
h/2
A ball of mass 2.0 kg is thrown vertically upward from the top of a building. The ball’s velocity v is given as a function of time t by the equation v(t) = R - St, where R = 5 m/s and S = 10 m/s2. The positive direction is upward.
If the ball reaches the ground at t = 2.0 s, what is the height of the building?
10 m
For the block shown above (see smartboard slide), which of the following is the best equation for describing the position x(t) of the block as a function of time t ?
x(t) = 1/2 a t2 + vit +xi
vectors A and B are given as:
A = 6i -7.5j
B = 5i + 3j
What is the magnitude of A+B
10.04
An object of unknown mass is initially at rest and dropped from a height h. It reaches the ground with a velocity v1.
The same object is then raised again to the same height h but this time is thrown downward with velocity v1.
It now reaches the ground with a new velocity v2
How is v1 related to v2?
v2 = sqrt(2)*v1
vectors A and B are given as:
A = 6i -7.5j
B = 5i + 3j
What is the direction of A+B (CCW from +x axis)
337.7 degrees