2. 1D Motion / Kinematics

Which statement best describes the difference between $\mathrm{positive}$ and $\mathrm{negative}$ acceleration?

Which statement is true about $a:$ acceleration?

In a lab experiment, a cart is pushed by a variable number of identical fans. How will increasing the number of fans affect the cart's acceleration, assuming all other factors remain constant?

Which of the following best describes negative acceleration ($a<0$)?

A motorcycle moves along a straight road, and its velocity is recorded at each second as follows: at $1$ s, $0$ m/s; at $2$ s, $0$ m/s; at $3$ s, $2$ m/s; at $4$ s, $5$ m/s. At which second does the motorcycle first begin to have positive acceleration?

Which of the following examples accurately describes an object that is accelerating?

Which of the following is an example of acceleration?

Suppose an object is in free fall near Earth's surface and air resistance is negligible. Each second, the object falls:

A car sits on an entrance ramp to a freeway, waiting for a break in the traffic. Then the driver accelerates with constant acceleration along the ramp and onto the freeway. The car starts from rest, moves in a straight line, and has a speed of $20$ m/s ($45$ mi/h) when it reaches the end of the $120$-m-long ramp. How much time does it take the car to travel the length of the ramp?

An automobile is originally at rest at $s=0$. If it accelerates uniformly at $a=2m/s^2$, what is its position after $t=3s$?

A car's velocity changes from $10m/s$ to $8m/s$ in $5s$. What is the acceleration of the car?

Three objects, A, B, and C, each with different masses, are acted upon by the same net force. Which object experiences the greatest acceleration?