CBQ Physical Science Unit 7


Acrobat Art of mass m stands on the left end of a seesaw. Acrobat Bart of mass M jumps from a height h onto the right end of the seesaw, thus propelling Art into the air.

Art’s mass is 40 kg, Bart’s mass is 70 kg, and the height of Bart’s initial jump is 4 meters.

A] How high is Art propelled?
B] How fast is Art moving just before he lands?

S – V – S (sketch, define variables, solve)

CBQ Physics U4: Physical Science U5: Impulse & Momentum

CBQ 3:  The first problem is more difficult. Using the thrust burn time and mass of the Falcon 9 reusable rocket’s 2nd stage, calculate the its velocity after a second stage boost phase burn.

Less challenging:  A diver pushes SpongeBobSquarePants with a force of F= 1,000 N for 10 seconds. SpongeBob’s mass is 1 kg. What is SpongeBob’s momentum after the push? What is his velocity?  (hint: use the impulse – momentum theorem).

Ft = delta p = mv
v = Ft/m = (1,000 N)(10 s) / (1 kg)


medium deifficulty problem: 2 skaters, he – 80kg, 4 m/s, she – 40kg, 8 m/s
she jumps in his arms and they travel off together — find their velocity.
(80)(4) + (40)(8) = (80+40) vfinal
vfinal = 640/120 = 5.33m/s

Please note: Physics Unit Plan needs to be updated to include U4: Impulse – Momentum, Theorem