Solving Word Problems in Science Name:______Period #:______These seven steps should set you up for correctly solving word problems in this, and hopefully other classes. In this class, I expect you not to skip any steps.
1. Underling the variables and circle the values. (If there is no variable listed for a value, write it in next to the number.) 2. Box the variable you are trying to find. 3. List the variables and values in a column. 4. Find and write the equation that has the variable you are looking for alone on one side of the equal sign. 5. Plug in the values you know for the variables in the equation. 6. Solve the equation. 7. Circle your answer and check your units.
Let’s do an example:
A person with a mass of 75 kg is accelerated to 3 m/s2. How much force was applied to him?
First we underline the variables and circle the values. Variables are components that can have different values. In this example, the variable of mass has a value of 75 kg. So the problem above would look like this:
A person with a mass of 75 kg is accelerated to 3 m/s2. How much force was applied to him?
Now we put a box around the variable that we don’t have a value for:
A person with a mass of 75 kg is accelerated to 3 m/s2. How much force was applied to him?
Now we list the variables and their values a column with a question mark for the value(s) we are missing: m= 75 kg a= 3 m/s2 F=?
Our equation with F alone and both m and a in it is F=ma, so we write this down then plug in values and solve. m= 75 kg F=ma a= 3 m/s2 F=(75kg)(3 m/s2) F=? F=225 kgm/s2 F=225 N
That’s it! Use this method to solve the equations in the rest of this worksheet. Here are the equations and values you might need: 2 F=ma a=F/m m=F/a agravity on earth=10m/s
11/10 1 1. A truck with a mass of 1500 kg is decelerated at a rate of 5m/s2. How much force did this require?
2. A pitcher accelerates a baseball with a mass of 1.5 kg at 6m/s2. How much force does this take?
3. A student starts a food fight by throwing a 0.5 kg burrito at some girl he likes. He throws it kind-of hard so he accelerates it at 3 m/s2. How much force did this take?
4. A hunter shoots a 2 kg arrow accelerating it at 15m/s2. How much force does this require?
5. A thug pushes some 100 kg punk with 300 N of force. How much is the punk accelerated?
11/10 2 6. A batter hits a baseball with 500 N and the ball is accelerated at 25 m/s2. What is the mass of the ball?
7. A 5 kg book rests on a table. How much force is it exerting on the table? (Hint: think about acceleration due to gravity.)
8. A cannon shoots a 40 kg ball at a sailing ship and when it hits the wall of the vessel it applies 2000N of force. How much was it decelerated?
9. How much force do you push down on the earth with? (Hint: 1kg is about 2 pounds).
10. The acceleration from gravity on the moon is 1.6 m/s2. How much less force would you apply standing on the moon?
11/10 3