MCAT Khan Physical Processes
For a 3 second period of time, a 50kg wooden crate slides across the concrete floor at exactly 5 m/s. The coefficient of kinetic friction between the wooden crate and the concrete floor is 0.2. What is the net force of this crate during this 3 second period?
0 N (there is constant velocity and no net force)
A 100kg block of wood is traveling with a constant velocity on ice. What is its normal force?
1000 N
A 60kg circus performer is suspended by 4 50ft wires high above an anxious crowd. The wires are all at an angle of theta between the ceiling and the performer. Which of the following describes the vertical component of force acting upon a single wire?
147 N
A child pushes a 100kg refrigerator with a force of 50 N, but the refrigerator does not move. Suppose the coefficient of static friction between the floor and the refrigerator is 0.4. What is the force due to friction in this scenario?
50 N
An elevator with a passenger accelerates upwards from rest at a value of 3 m/s^2. What is the normal force of the elevator on the passenger if the passenger has a mass of 50kg?
650 N
A tug of war match is started, team 1 pulls with a force of 70N, while team 2 pulls with a force of 75N. What is the tension in the rope?
70N
An object is dropped from the top of the Empire State Building. Which of the following statements best describes the motion of the object as it experiences air resistance during its downward fall?
Its acceleration will decrease until the object starts moving with a constant speed
Which of the following expressions is representative of total power output?
P x Q (P = pressure, Q = volumetric flow rate)
Which of the following statements is true regarding a rider in a roller coaster cart moving with a constant speed through a loop?
The rider is accelerating
Which of the following scenarios most accurately represents Pascal's law?
The volume displaced by piston 1 is equal to the volume displaced by piston 2 in a hydraulic lift.
An elevator's motion is through the action of a single cable. The elevator has a gravitational force of 2000 N. When the elevator is moving downwards at a constant velocity, how much tension is in the cable?
equal to 2000 N
A tank with height y is filled with water to the top and is placed at a height z above the ground. Currently the water level is 3m above the ground. At the bottom of the tank, there is a hole where the water can flow out when needed. Which of the following would increase the flow rate?
increase the size of the hole
When the gauge pressure is doubled, what happens to the absolute pressure?
it increases by a factor less than 2
According to your understanding of Bernoulli's principle and continuity equation, which of the following statements accurately describes the phenomenon of vascular flutter which occurs when an artery becomes constricted due to the accumulated plaque in its inner walls?
the constriction causes the pressure to drop and the vessel to collapse
According to Poiseuille's Law, which of the following statements correctly describe blood flow through arteries?
vasodilation by 20% will double the blood flow rate
