Physics White Board Review Formula Practice

What are the units for force? Newtons What are the units for work? joules What are the units for mass? grams What are the units for acceleration? m/s2 What are the units for distance? Meters or centimeters

Example 1: Work Formula The box to the left is pushed up the ramp. How much work was done to move the box up the ramp? 2 N W=Fd W = (2)(12) Work = 24 joules

Example 2: Net Force Formula 10 kilograms ??? The above box accelerated 3.4 m/s2.What is the force that was applied to the above box? F = ma F = (10)(3.4) F = 34 Newtons

Example 3: Average Speed Formula The graph to the right shows the motion of a cat over time. What was the cats average speed? S=d/t = 80/100 =0.8 m/s

What is the acceleration of the above box? Example 4 10 kilograms 12 Newtons of force What is the acceleration of the above box? F=ma 12 = (10)(a) 1.2 m/s2

Example 5 Nicholas pushes a dirt bike up a ramp with a force of 225 N. He uses 1,125 joules of energy to get the bike up the ramp. How tall must the ramp have been? W=Fd 1125 = (225)(d) Height (distance) = 5 meters

What is the speed of the object after 6 seconds? Example 6 What is the speed of the object after 6 seconds? Time (seconds) Distance (meters) 2 3 6 7 8 5 S= d/t S = 3/6 0.5 m/s

Example 7 The graph to the right shows the motion of a cat over time. What was the cats speed for the first 40 seconds? S = d/t = 20/40 0.5 m/s

Example 8 The graph to the right shows the motion of a cat over time. What was the cats speed between 40 and 60 seconds? 0 m/s …the cat isn’t moving!!!

Example 8 The chart below shows the mass of four different types of balls. Each ball is sitting on top of the ramp that is also shown below. Which ball would has the greatest potential energy while sitting on top of the ramp? 4 m Ball A Ball B Ball C Ball D 2 m Ball Material Mass A Metal 63 g B Styrofoam 7.4 g C Glass 59 g D Plastic 9.2 g

Which of the following describes the energy transformations that takes place in a burning log? Chemical energy to radiant and thermal energy Chemical energy to electrical and thermal energy Potential energy to chemical energy Kinetic energy to radiant and thermal energy

Which of the diagrams show the conversion of chemical to mechanical energy? 1 and 2 1 and 3 2 and 4 3 and 4

Mrs. Tucker threaded a string through a straw, blew up a balloon and taped a balloon to a straw as shown below. When she releases air from the neck of the balloon what will happen? Following Newton’s 2nd Law, the balloon and the straw will move toward point one. Following Newton’s 1st Law, the balloon and straw will spin on the string. Following Newton’s 3rd Law, the balloon and straw will move towards point 2. Following Newton’s 1st Law, the balloon and straw will not move.

Biceps and triceps are muscles in the arm Biceps and triceps are muscles in the arm. When biceps expand, triceps contract, allowing the arm to move. Which of Newton’s Laws of Motion best explains the forces at work by the muscles in the arm? Newton’s 1st Law of inertia Newton’s 2nd Law of force and acceleration Newton’s 3rd Law of action-reaction Newton’s Laws do not apply to human body parts.

When a car suddenly stops, the objects in the back seat are thrown forward. This is due to- Newton’s 1st Law of Motion Newton’s 2nd Law of Motion Newton’s 3rd Law of Motion The Universal Law of Gravitation

The tendency of an object to resist changes in its motion is related to one of Newton’s laws. It is called- Acceleration Force Inertia Work