A light-rail commuter train accelerates at a rate of
1.20m/s2.
How long does it take to reach its top speed of 80.0
km/h, starting from rest?
The same train ordinarily decelerates at a rate of
1.45m/s2. How long does it take to come to a stop from its top speed?
In emergencies the train can decelerate more rapidly, coming to rest from 80.0km/h in 7.60s. What is its emergency acceleration in m/s2? (The initial velocity is in the positive direction.)
While entering a freeway, a car accelerates from rest at a rate of
2.45 m/s2 for 13.5s. (Define the positive direction to be the direction of the acceleration.)
How far does the car travel in those 13.5s?
What is the car’s final velocity?
A fireworks shell is uniformly accelerated from rest to a velocity of
52.0 m/s over a distance of 0.210m. (Define the positive direction to be the direction of motion.)
Find the time over which the acceleration occurred.
Calculate the acceleration.
A dolphin in an aquatic show jumps straight up out of the water at a velocity of 11.7m/s.
How high does his body rise above the water?
How long is the dolphin in the air? Neglect any effects due to his size or orientation.
The brakes are applied to a car traveling at
32.0m/s on a dry, level highway. A typical value for the magnitude of the car’s acceleration while braking is 4.25m/s2.
How long does it take the car to stop?
How far does the car travel, starting from the moment the brakes are applied?
A rock is thrown vertically upward from the edge of a cliff. The rock reaches a maximum height of d =13.0m above the top of the cliff before falling to the base of the cliff, landing tf =6.40s after it was thrown. What is the height h of the cliff?
Part 1 +
Identify the figure which correctly diagrams the problem.
a.
b.
c.
d.
Part 2
How high is the cliff?
A particle is initially moving east at a speed of
34.0m/s and experiences an acceleration of magnitude 2.00 m/s2, directed west. (Define the positive direction to be toward the east.)
Part 1 +
Which statement correctly describes the particle’s initial velocity and acceleration?
a. The particle has a negative initial velocity and a positve acceleration.
b. The particle has a negative initial velocity and a negative acceleration.
c. The particle has a positive initial velocity and a positive acceleration.
d. The particle has a positive initial velocity and a negative acceleration.
Part 2
Find the position (relative to the position at t= 0.00s) and velocity of the particle at t = 3.75s.
position:
The (+ or -) sign indicates the position of the particle is:
(No answer given)west of its original positioneast of its original positionnone of the above
Correct answer, well done.
Marks for this submission: 0.250/0.250.
velocity:
The (+ or -) sign indicates the direction of the velocity is:
(No answer given)toward the westtoward the eastnone of the above
Correct answer, well done.
Marks for this submission: 0.250/0.250.
