Phy_Prac_Gravity in Kinematic Equations 🙃Quizizz_8.15

An apple drops from a tree and hits the ground at a speed of 16 m/s. How long did it take to fall?

• 1.6 s

• -1.6 s

• 157 s

• -157 s

Answer explanation

Did you make the 16m/s negative? It is moving in the downward direction.

Remember that time cannot ever be negative, it is a scalar.

Did you chose the vf = ... equation?

Tags

NGSS.MS-PS2-4

An apple drops from a tree and hits the ground at a speed of 16 m/s. What is its displacement?

• -13 m

• +13 m

• +157 m

• -157 m

Answer explanation

Since the apple was moving downward, it's displacement is negative.

Did you use the vf^2=... equation?

A skydiver jumps from a helicopter hovering at high altitude. If we ignore air resistance, what will his velocity be 2.2 s after jumping?

• +21.6 m/s

• +23.7 m/s

• -21.6 m/s

• -23.7 m/s

Answer explanation

In what direction is he falling? Your sign on the velocity should be in the direction he is moving.

Did you use the vf = ... equation?

Tags

NGSS.MS-PS2-2

You flip a coin with a speed of 1.7 m/s straight up. It travels upward 0.15 m (15 cm) above your thumb. How long did it take the coin to reach its highest point?

Give your answer with 3 decimal places. Only give the number answer, leave off the units.

Mathematical Equivalence

ON

Answer explanation

Did you realize that the final velocity at the top of its path is 0 m/s?

So, you can use several equations to solve this. The simplest one is vf =...

Tags

NGSS.HS-PS2-1

Kenny Klutz throws his physics book straight up into the air with a speed of 3.2 m/s. How high up in the air will it go?

• 0.522 m

• 31.36 m

• 3.06 m

• 0.327m

Answer explanation

Since time is not given and not the unknown, choose the equation that does not have a t in it.

vf^2 = ....

Tags

NGSS.HS-PS2-1

Think about this one...no need to calculate.

Kenny Klutz throws his physics book straight with a speed of 2 m/s.

If he catches it, how fast will it be moving? Ignore air resistance.

• -2 m/s

• +2 m/s

• -9.8 m/s

• +9.8 m/s

Answer explanation

What slows down the book on the way up?

What speeds the book back up on the way down?

Are these the same? Would that mean that the speeds on the way up are a mirror image of the speeds on the way back down?

Think about this one...no need to calculate.

Kenny Klutz throws his physics book straight with a speed of 2 m/s.

He catches it! What is the book's acceleration the entire time it is in the air? Ignore air resistance.

• -2 m/s^2

• +2 m/s^2

• -9.8 m/s^2

• +9.8 m/s^2

Answer explanation

What slows down the book on the way up?

What speeds the book back up on the way down?

What value do both of these have in common?

Tags

NGSS.MS-PS2-4

Mars has an acceleration due to gravity of -3.47 m/s². How far will a quarter dropped from rest on Mars fall in 1.5 s?

Ignore air resistance.

• 11 m

• 3.9 m

• 5.2 m

• 2.31 m

Answer explanation

Did you use Mars' gravity instead of 9.8?

Since the questions asked how far it fell, the answer does not require as (-) sign.

Did you use the x = vit.... equation?

Tags

NGSS.MS-PS2-2

On earth, what speed will a quarter dropped from rest acquire in 1.5 s?

• 14.7 m/s

• 9.8 m/s

• 6.5 m/s

• 11 m/s

Answer explanation

Since the question asked for speed, there is no need to give a negative answer as speed is a scalar.

Did you choose the vf=... equation?

Tags

NGSS.MS-PS2-4

NGSS.MS-PS2-2

With more gravitational acceleration on the earth than on Mars, the quarter will fall (faster/slower) on earth. So acceleration due to gravity and speed are (directly/inversely) related.

• faster, directly

• slower, inversely

• faster, inversely

• slower, directly

Tags

NGSS.MS-PS2-2