PART A.

Activity 3 - Effect of Lubricant

1. Rub your hands together for 1 minute. Then put your hands on your cheeks. Observe what you feel.

2. Repeat the step 1 but put a small amount of lotion on your hands. Is it as hot as before? Why? Try with baby oil and powder.

PART B.

1. Which will require a greater force: to start the motion of a heavy box or to keep the box moving with constant speed?

2. Why is it difficult to walk with new leather shoes on a polished floor?

3. How can an adjustable inclined plane be used to measure the coefficient of static friction and coefficient of kinetic friction?

4. The coefficient of static friction and coefficient of kinetic friction between a refrigerator and the floor are 0.45 and 0.38, respectively. If the refrigerator weighs 1000 N, find the horizontal force needed to (a) start the motion of the refrigerator, (b) to keep the refrigerator moving at a constant speed once it started moving. If a horizontal force of 400 N is applied, what will happen to the refrigerator? In this situation, what is the value of friction?

5. Explain the usefulness of a parachute for safe landing.

Please help me to answer this individually and short but detailed explanation. Thank you