Science Fact File Grade 8 | Chapter # 8, Force and Pressure | Test Yourself Q/A | Complete Chapter
Science Fact File Grade 8 | Chapter # 8, Force and Pressure | Test Yourself Q/A | Complete Chapter 00:00 Answer Buddy Intro 00:10 Test Yourself, Page # 128 00:51 Test Yourself, Page # 129 01:12 Test Yourself, Page # 131 01:52 Test Yourself, Page # 133 02:14 Test Yourself, Page # 134 Questions covered in this video: What are balanced forces? Give examples. Explain what a resultant force is. What are the two effects of unbalanced forces acting on an object? A car is travelling along a straight road. The force pushing the car forwards is 1000 N. Describe the motion of the car if the force of the air resistance against it was: a. 1000 N b. 3800 N What appears to happen to the weight of an object when it is submerged in water? Explain why this happens. Water has a density of 1 g/cm³. What does this mean? Explain how balanced forces enable a boat to float. The Dead Sea has a very high salt content. Explain why it is easier for a swimmer to float in the Dead Sea than in a swimming pool containing fresh water. What is pressure? Which end of a pencil gives the lowest pressure? How is pressure affected by: a. Surface Area? b. Force? Explain why a person who sits on a drawing pin hurts himself, yet someone lying on a bed of nails does not. A woman wearing shoes with stiletto heels weighs 550 N. The area of each stiletto heel is 1 cm². Calculate the pressure of each heel on the floor. The same woman wears flat shoes with heels with an area of 10 cm². What is the pressure on each heel now? Which type of heel is less likely to damage a wooden floor? Explain why. Explain why air can be squashed. Why does compressing a gas cause it to heat up? Describe the link between the volume and the pressure of a gas. Explain why the pressure in a liquid increases with depth. How does the density of a liquid affect pressure? Describe how you can show that the pressure in a liquid does not depend on the shape of its container. Discuss possible reasons for why submarines need strong, thick walls. A tank for storing liquid has a base of area 1.5 m². What is the pressure on the base of the tank when it contains: a) Water weighing 4500 N? b) Oil weighing 6000 N?
