Physics
posted by y912f on .
please check:
1. A piece of chalk is dropped by a teacher walking at a speed of 1.5 m/s. From the teacher's perspective, the chalk appears to fall.
STRAIGHT DOWN
2. Which is the force of an acceleration?
FORCE
3. A freebody diagram of a ball falling in the presence of air resistance would show
A DOWNWARDS ARROW TO REPRESENT THE FORCE DUE TO GRAVITY AND AN UPWARD ARROW TO REPRESENT THE FORCE OF AIR RESISTANCE
4. As an object falls toward Earth
THE OBJECT EXERTS A DOWNWARD FORCE ON EARTH
5. A net force of 6.8 N accelerates a 31 kg scooter across a level parking lot. What is the magnitude of the scooter's acceleration?
0.22 M/S^2
6. A hocky stick hits a puck on the ice. Identify an actionreaction pair in this situation
THE STICK EXERTS A FORCE ON THE PUCK; THE PUCK EXERTS A FORCE ON THE STICK
7. Calculate the following, expressing the answer in scientific notation with the correct number of signifant figures: (8.86 + 1.0 * 10^3) / 3.610 * 10^3
i don't really get this one

I don't understand 2.
On 4, forces occur in pairs, the downward force on the object is matched by an upward force on Earth.
7.
when multiplying or dividing the number of significant digits in the answer is equal to the leesor number of significant digits in either of the original numbers.