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A collection of physics warm-up questions and discussions covering topics such as forces, motion, equilibrium, and vectors. Includes quizzes and dimensional analysis.
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Physics201/211 • Warm-up Question • A spaceship has a force, F1, acting on it in the +x direction. It also has two other forces, F2 and F3 acting 120o up and 120o down from the +x direction, respectively. If the spaceship is traveling at a constant speed in the +x direction and the magnitude of all the forces is the same, which statement is true? • The spaceship will begin to slow down • The spaceship will begin to accelerate downward • The spaceship will begin to speed up in the positive y direction • The spaceship will begin to speed up in the positive x direction • None of the above
Physics201/211 What must the mass of m3 be to slide m2 out from under m1? m1=1kg m2=3kg m3
To go to a football stadium from your house, you first drive 1000m north, then 500m west, and finally 1500m in a direction 20o south of west. (a) relative to your home, the football stadium is in what direction? How far away is your house from the stadium in a straight line?
Walking along the beach you notice there is an island at an angle of 30o with respect to the shore. You then walk 50m along the shore, ending on the other side of the island. A measure tells you the island is now 40o out from the shore. How far away is the island from the shore?
Physics201/211 Static Equilibrium A 1000 kg steel beam is supported by two cables. What is the tension in each cable? 70 60
Physics201/211 A 90 kg man is standing on a scale that determines weight. This scale is in an elevator that is accelerating in the upward direction. Will the man’s 90 kg: A. increase B. decrease C. stay the same
Physics201 • Quiz Question • A gerbil runs 85cm in a straight line. This takes it 5s. Then the gerbil turns around and runs in the opposite direction 65cm. This takes it 3s. What is the magnitude of the gerbil’s average velocity for the entire trip? • 21.7cm/s • 17.0cm/s • 19.3cm/s • 0.25cm/s • 0.667cm/s • 20.0cm/s
Physics201 • Discussion Question • What is the total distance Δx traveled by the particle? • 50m • 40m • 30m • 20m
A father is now three times as old as his son. Twelve years ago he was six times as old as his son. Find the present age of each.
Physics201/211 It takes 0.2 second for the back end of a 1500kg car to crumble within 2m of the front end, in a collision with an immovable concrete wall. What is the net force that acts on the front bumper during this time?
Physics201 Quiz Question Which plot represents the velocity vs. time of the particle represented by the position vs. time graph?
Physics201 Discussion Question Below a plot of the position vs. time has been drawn. Draw the corresponding acceleration and velocity graphs.
Physics201 Discussion Question Below a plot of the position vs. time has been drawn. Draw the corresponding acceleration and velocity graphs.
Physics201 • Quiz Question • Use dimensional analysis to determine what the area under the curve represent? • Average Velocity • Speed • Acceleration • Distance traveled
Physics201 Discussion Question Below a plot of the velocity vs. time has been drawn. Draw the corresponding acceleration and position graphs.
Physics201 Discussion Question Below a plot of the position vs. time has been drawn. Draw the corresponding acceleration and velocity graphs.
Physics201 Quiz Question
Physics201 Describe what’s happening What is Fred’s average speed? What is Brutus’s average speed?
Physics201/211 Describe what’s happening
Physics201/211 A 90 kg man is standing on a scale that determines weight. This scale is in an elevator that is accelerating in the upward direction. Will the man’s apparent weight: A. increase B. decrease C. stay the same
Physics201/211 a.) How much force does an 80 kg astronaut exert on his chair while sitting at rest on the launch pad? b.) How much force does an 80 kg astronaut exert on his chair while accelerating straight up at 10 m/s^2?
Physics201/211 No Friction A 10 kg crate is being slid across a frictionless floor by a 40 N force acting at an angle of 35 degrees below the horizontal. How far will the crate slide after 10 seconds?
Physics201/211 Friction a.) A 10 kg crate is being pushed on by a 40 N force acting at an angle of 35 degrees below the horizontal. What coefficient of static friction will keep this crate from moving? b.) If the coefficient of kinetic friction is 10% less than that of static friction, what will the acceleration of the crate be?
Physics201/211 • Discussion Question • Standing on ice, a father and daughter face each other, pressing flat hands together. They push off each other and start moving away from each other. Which of these statements is correct. • The daughters acceleration is the same as here fathers • Both are decelerating since their push is in the opposite direction of their motion • While in contact their hands are not moving • After they push off, both leave with the same speed • None of the above
Physics201 • Discussion Question • What is average velocity of the particle over the time interval Δt=50.0s? • 30m/s • 0.6m/s • 2.0m/s • 10m/s
Physics201/211 Find the tension in each cable and the applied force F required for that the system to not move.
Physics201 Discussion Question Below a plot of the position vs. time has been drawn. Draw the corresponding acceleration and velocity graphs.
Physics201/211 What must the mass of m3 be to slide m2 out from under m1? m1=1kg m2=3kg m3