Sometimes, always, never

Today in intro physics, after introducing the new unit, we did test review using “sometimes, always, never,” which I learned from Frank Noschese.  We have covered projectile motion, Newton’s 2nd Law, and Uniform Circular Motion.

Here were our statements:

1. Constant speed means zero acceleration.
2. Normal force points in the opposite direction of weight.
3. When an object is on a ramp, the acceleration is always down the ramp.
4. When a projectile hits a surface, it’s final velocity is zero.
5. For an object in free-fall, its speed at maximum height is zero.
6. In projectile motion,the horizontal component of acceleration is 9.8 m/s/s.
7. For uniform circular motion, velocity and acceleration are 90 degrees apart.
8. Given two velocity components, the speed is found by simply adding them together.

The rules are students must draw / describe two examples, no matter whether they think it’s always, sometimes, never.