When we're working problems that involve a pendulum, we almost always IGNORE anything else besides gravity.
Anything else besides gravity that could influence the motion of a pendulum is something that we would eliminate if we could.
Those are air resistance, mass of the string, friction at the top suspension point, and the Coriolis force, due to the Earth's rotation, that tries to change the plane of the pendulum's swing.
This question is probably fishing for the answer "<em>friction</em>".
Answer:
2.47 s
Explanation:
Convert the final velocity to m/s.
We have the acceleration of the gazelle, 4.5 m/s².
We can assume the gazelle starts at an initial velocity of 0 m/s in order to determine how much time it requires to reach a final velocity of 11.1111 m/s.
We want to find the time t.
Find the constant acceleration equation that contains all four of these variables.
Substitute the known values into the equation.
- 11.1111 = 0 + (4.5)t
- 11.1111 = 4.5t
- t = 2.469133333
The Thompson's gazelle requires a time of 2.47 s to reach a speed of 40 km/h (11.1111 m/s).
Answer:
12N to the right.
Explanation:
There is a force of 12N upwards and a force of 12N downwards: these cancel out.
Assign a negative value to forces towards the left, and a positive value to the forces towards the right: -3N and +15N
Combine them: -3N+15N = 12N
The net force has a magnitude of 12N, and since our answer was positive, it acts towards the right.
