PHYS 250 MT2 CORRECT QUESTIONS
& ANSWERS(RATED A+)
You and a friend are moving a very heavy and irregular piece of furniture across a
room. You are lifting it to prevent it from scratching your wooden floor. Your friend
lets you pick where you are going to hold it and your friend will hold it at the other
end (or some other place you tell your friend to hold it). To make it easier on
yourself, you would:
A.Hold the end closer to the center of mass (your friend holds the other end).
B.Hold the end farther from the center of mass (your friend holds the other end).
C.Hold it at the center of mass and have your friend hold it from one of the other
ends.
D.It doesn't matter where you pick - you'll both have to exert the same force no
matter where you hold it.
E.Hold either end since you have to exert the same force no matter which end you
pick. - ANSWERB.Hold the end farther from the center of mass (your friend holds the
other end).
Two acrobats flying through the air grab and hold onto each other in midair as part of
a circus act. One acrobat has a mass of 60 kg and has a horizontal velocity of 5 m/s
just before the grab.Another acrobat has a mass of 50 kg and has a horizontal
velocity of -3 m/s just before the grab. Their horizontal velocity immediately after they
grab onto each other is: - ANSWERm1iv1i + m2iv2i = (m1 + m2) v2f
(60*5) + (50*-3) = (60 +50) v2f
v2f = 1.4 m/s
Your kid sister is making a mobile representing the earth, moon, and sun for her
grade school science fair. The ruler is provided below to help you determine
positions of the three hanging balls, of mass 15 g, 5 g, and 30 g, respectively. Of the
five options provided, where is the horizontal center of mass at which would you
connect a string to this mobile so that it would remain balanced when you hung it
from the string?(The rods and strings all have negligible mass compared to the
balls.) - ANSWERCoM = (m1r1 + m2r2 + m3r3)/ (m1 + m2 + m3)
CoM = 7.15 cm
An 60-kg diver stands at the edge of a lightweight diving board, which is supported at
two locations, as shown in the figure below. Determine the strength and direction of
the force exerted on the diving board by the right-most support. - ANSWER0 = -2Fgd
- 1.2 Fr
1.2Fr = 2 (60 * 9.8)
Fr = 980 N
What torque must your bicep muscle exert around your elbow if you are holding a
4.5kg (~10 lb) weight horizontally? Your forearm is 0.30 meters long and the muscle
exerts force atthe point furthest from the pivot point. - ANSWERtorque = rFsin(theta)
torque = (0.3)(4.5*9.8)sin(90) = 13.23 Nm
