Unit 1 check

Unit 1 check: Kinematics

10 questions from 5 lessons in Unit 1. Answer each one, and if you miss, follow the link back to where it is taught, then try again. Your score counts first tries.

Question 1 · from 1.1 · Sort it

Tap a statement, then the kind of quantity it gives.

Scalar

Vector

Question 2 · from 1.2 · Calculate

An elevator moves in a vertical shaft. Take up as positive, with positions measured from the ground floor. When a clock reads 4 s the elevator is at 30 m, and when the clock reads 12 s it is at 6 m. What is its average velocity over that interval?

Your answer m/s

Question 3 · from 1.3 · Calculate

A cart on a level track is moving east at 1 m/s at $t = 0$ . Its acceleration-time graph is a level line at $+ 2 {m/s}^{2}$ from 0 to 3 s, then a level line at $- 1 {m/s}^{2}$ from 3 s to 5 s. Take east as positive. What is the cart's velocity at $t = 5$ s?

Your answer m/s

Question 4 · from 1.4 · Sort it

A rider on a train moving at a steady velocity along a straight track and a person on the platform watch the same events. Air resistance is negligible. Tap each measurement, then where it belongs.

Depends on the observer's frame

The same in every inertial frame

Question 5 · from 1.5 · Match

A ball is thrown at 12 m/s from the edge of a flat roof, in five different directions, each one either toward the street or straight up. Take $+ x$ as horizontal, toward the street, and $+ y$ as up. Tap each throw, then the components of its launch velocity.

Question 6 · from 1.1 · Multiple choice

Right is positive. Arrows for the velocities of carts A and B are drawn to the same scale. Cart A's arrow points left and is twice as long as cart B's arrow, which points right. Which statement is correct?

Question 7 · from 1.2 · Decide and justify

Take east as positive. A car driving west speeds up from a velocity of $- 8$ m/s to $- 14$ m/s in 3 s. Is its average acceleration positive or negative?

Which reason supports your answer?

Setup for question 8

A student tracks a toy car on a straight track with a motion sensor, taking east as positive. The car starts at rest, drives west, and comes to rest again. Within each 2-second stretch (0 to 2 s, 2 to 4 s and 4 to 6 s) its acceleration is constant, so its velocity changes steadily between readings.

Velocity of the toy car
Time (s)	Velocity (m/s)
0	0
1	−2
2	−4
3	−4
4	−4
5	−2
6	0

Question 8 · from 1.3 · Calculate

Using the toy car's velocity table, with east as positive, what is the car's displacement from 0 to 6 s?

Your answer m

Setup for question 9

A new situation, and this time the motion is vertical. A freight elevator rises at a steady 2 m/s. A bolt works loose from its ceiling and falls. Ria rides in the elevator, and Sam stands still in the lobby, watching through the glass doors. Before you calculate anything, decide whose frame makes the fall simplest to describe.

Question 9 · from 1.4 · Decide and justify

A freight elevator rises at a steady 2 m/s. A bolt comes loose from its ceiling and falls. Air resistance is negligible, and up is positive. Ria rides in the elevator, and Sam stands still in the lobby. Who measures the bigger acceleration for the falling bolt?

Which reason supports your answer?

Question 10 · from 1.5 · Calculate

By lunchtime, a hiker's displacement from camp is 7.0 km east and 4.0 km north. Take east as $+ x$ and north as $+ y$ . At what angle north of east does her displacement point? Give your answer to the nearest degree.

Your answer degrees

0 of 10 answered.