Velocity and Gravity Flashcards
7 cards from real Bennett Mechanical Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Velocity and Gravity flashcards as text
A train decelerates from 30 m/s to 0 m/s in 10 seconds. What is its acceleration?
Answer: -3 m/s²
Acceleration is (0−30)/10 = −3 m/s², negative because it slows down.
Terminal velocity occurs when which forces are balanced?
Answer: Gravity and air resistance
At terminal velocity the upward air resistance equals the downward gravity, so speed stays constant.
Which object would reach terminal velocity sooner when falling?
Answer: A large open parachute
The parachute's large surface creates more air resistance, balancing gravity at a lower speed sooner.
A ball thrown upward at 20 m/s takes about how long to reach its highest point?
Answer: 2 seconds
Time equals velocity divided by g, 20 ÷ 10 = 2 seconds.
If you double an object's speed, how does its velocity vector change in magnitude?
Answer: It doubles
The magnitude of velocity is the speed, so doubling speed doubles the velocity magnitude.
Weight is best described as which of the following?
Answer: The force of gravity on an object
Weight is the gravitational force acting on an object's mass.
A cyclist moving north at 10 m/s turns to move east at 10 m/s. Has the velocity changed?
Answer: Yes, direction changed
Velocity is a vector, so a change in direction means velocity changed even at constant speed.