Vertical Motion
You have two baseballs. You drop the first object from rest and throw the second in the downward direction from the same height.
Which of the two will have the greatest acceleration?
They both have the same acceleration: -9.8 m/s2
A 0.03 Kg arrow and a 200Kg boulder are launched horizontally out of a building. The arrow travels at 200 m/s while the boulder travels at 0.1m/s. Assuming air resistance is negligeable, determine which object will land the farthest.
The arrow.
You have two baseballs. You drop the first object from rest and throw the second in the downward direction from the same height.
Which object will travel the greatest distance?
They both travel the same distance.
If an object is changing it's velocity over time it is...
Accelerating
A bowling ball, a basketball, and a tennis ball are all dropped from the same height at the same time. Ignoring air resistance, which object will hit the ground first?
All three at the same time.
A 0.10Kg baseball and a 75Kg desk are launched horizontally out of a building. The Baseball travels at 42 m/s while the desk travels at 0.3m/s. Assuming air resistance is negligeable, determine which object will land first.
They both land at the same time. (Horizontal and vertical motion are independent)
A marble rolls off a table at 3m/s. It takes the marble 2 seconds to hit the ground. An identical marble is dropped from the same height. How long does it the second marble to hit the ground?
2 seconds as well!
TRUE or FALSE
A Motion dot diagram of an accelerating object would have dots getting farther and farther from each other.
TRUE
True or False:
The horizontal velocity of an object determines how long it takes to fall.
False, it's only due to it's VERTICAL acceleration due to gravity.
A jet must achieve a speed of 120 m/s in order to take off. The plane starts at rest and accelerates for 35 seconds to reach this speed.
What is the acceleration of the jet?
a = (vf - vi ) / t
= (120 - 0)/35
= 3.43 m/s2
An object is thrown UP with a perfectly vertical path. What is the object's acceleration and velocity at the maximum height?
Velocity: 0 m/s;
Acceleration: -9.8 m/s2
0 m/s
A basketball is dropped off the top of a cliff. It hits the ground after falling for 20s. How tall is the cliff? (ignore air resistance)
1960m
An airplane must achieve a speed of 90 m/s in order to take off. The plane starts at rest and accelerates at 1.8 m/s2 for 50 seconds to reach this speed.
How long must the runway be in order for the plane to take off safely?
Δx = vi*t+(1/2)*a*t2
= 1/2 * 1.8 * 502
= 2250m
A basketball is dropped off the top of a 200m cliff. . How long will it take to hit the ground?
t = 6.4s
a = -9.8 m/s2
You drop an object from a 75m tall tower on a strange planet. It took 5s to reach the ground. What is the acceleration due to gravity on this planet?
a = 6 m/s2
A race car starts from 3m/s and accelerates at 8 m/s2 for 12 seconds.
What is the car's final velocity?
Vf = 99 m/s
You drop an object from 85m tall tower on a strange planet. The acceleration due to gravity on this planet is 12 m/s2. How long will it take the object to fall?
t = 5.32s
An arrow is shot directly up at 58m/s. It takes 10s to reach it's max height. How high up has the arrow gone?
height = 90m
A race car starts from rest and accelerates at 4 m/s2 for 8 seconds. The car then slams on the brakes and comes to a stop in 4 seconds.
How far does the car go in total?
break this up into two problemsΔxacc = vi*t + 1/2*a*t2
= 0*8s + 1/2*4*42 = 128m
Δxdec = vi*t + 1/2*a*t2 [v=0+4*8] and [a=-32/4]
= 32*4 + 1/2*(-8)*42 = 64m
Δxtot = 192m