PODAR Name: Subject: Science Std: VIII Roll No: Date: Topic: Force & Pressure 1. In Fig, two boys A and B are shown applying force on a block. If the block moves towards the right, which one of the following statements is correct? (a) Magnitude of force applied by A is greater than that of B. (b) Magnitude of force applied by A is smaller than that of B. (c) Net force on the block is towards A. (d) Magnitude of force applied by A is equal to that of B 2. During dry weather, while combing hair, sometimes we experience hair flying apart. The force responsible for this is (a) force of gravity. (c) force of friction. (b) electrostatic force. (d) magnetic force 3. Which of the following statements is correct about pressure of water? (a) Pressure at A> Pressure at B> Pressure at C (b) Pressure at A-Pressure at B-Pressure at C (c) Pressure at A< Pressure at B>Pressure at C (d) Pressure at A< Pressure at B 4. A water tank has four taps fixed at points A, B, C, D as shown in Fig. The water will flow out at the same pressure from taps at (a) B and C (c) C and D (b) A and B (d) A and C

Fill in the blanks: A cylindrical wooden log (d= 20 cm, L =50 cm) is tied to an anchor and dropped overboard somewhere in Pacific ocean. Determine the tension in the rope when the anchor touches the sea floor. Note the SGWood = 75 and SGgeawater = 1.03. %3D Answer: N (whole number)

In this example, we are going to take a look at a different type of friction, one that is not described by equations for static-friction force and kinetic-friction force. When an object moves through a fluid (such as water or air), it exerts a force on the fluid to push it out of the way. By Newton's third law, the fluid pushes back on the object, in a direction opposite to the object's velocity relative to the fluid, always opposing the object's motion and usually increasing with speed. In high-speed motion through air, the resisting force is approximately proportional to the square of the object's speed v; it's called a drag force, or simply drag. We can represent its magnitude FD by FD=Dv2, where D is a proportionality constant that depends on the shape and size of the object and the density of air. When an object falls vertically through air, the drag force opposing the object's motion increases and the downward acceleration decreases. Eventually, the object reaches a terminal…

Case 1 traffic light: Weight of hanging object: 370g Angle 1: 130 degrees Angle 2: 100 degrees Measured tension 1: 3.0 N Measured tension 2: 4.2 N Please answer with equations and calculations.