When we sit on them all of a sudden, the seats are compressed. The seats are also fitted with springs to reduce their hardness. The springs increase the duration of impulse and hence reduce the force. When vehicles more over an uneven road, they experience impulses exerted by the road. The vehicles are fitted with springs to reduce the hardness of the shock. This will slow down his rate of change of linear momentum and lesser force will be involved. He is advised to run over some distance on the platform or road along with (in direction f) the train or bus. If he jumps down suddenly from the moving train or bus and tries to stand on his feet, his body will fall forward due to inertia of motion. Jumping down of a passenger from a moving train or bus :Ī passenger sitting in a moving train or bus has momentum, When he jumps down and stands on platform or road, his momentum becomes zero. His momentum changes slowly requiring a lesser force of action from the sand. If someone jumps from a height on a heap of sand below, his feet move inside the sand very slowly. In reaction, the ball also applies lesser force and the hands of the player are not injured. As a result a small force is applied on the ball. By moving his hands, the cricketer takes longer time. Final velocity (v) Time of impact (t/s) Impulsive force (F/N) Result of the kick 1 45 0.3 300 GOAL / MISSED 2 25 0.2 250 GOAL / MISSED 3 30 0.6 100 GOAL / MISSED 4 30 0.2 300 GOAL / MISSED 5 30 0.6 100 GOAL / MISSED 6 10 0.While catching a fast moving cricket ball, the player moves his hands backward after catching the ball. The result of the calculation will determine whether it’s a goal or a missġ7 Kick no. WINTER Template 16 Do you want to play some games? INSTRUCTIONS: -You are allowed to discuss during the game -The task for each player is to calculate the questions given -Given that initial velocity of the ball is 0 ms -1 and mass of the ball is 2 kg. What are other applications of impulsive force in our daily lives? Can you explain? 15 Why does food stuff such as garlic can be pounded using mortar and pestle? Why a karate expert can break a pile of plank easily using his bare hand? 14 Compare the impulsive force if the baseball player wears a hard glove to catch the ball.
Why does the impact on car A is smaller compared to car B? A Bĭiagram 2 shows a baseball player wearing a soft thick glove to catch a ball during a baseball match. What is the impulse of the ball? ĪPPLICATION OF IMPULSIVE FORCE 13 Both cars travel at a velocity of 120 m/s and hits a wall. It hits a wall and bounces back in opposite direction with a velocity of 12m/s. HOW ABOUT IMPULSE? Impulse is defined as the changes of momentum Įxample: Figure shows a ball of mass 20 g travelling at 15m/s.
What is the impulsive force hitting the target? The harder the surface, the shorter the contact time on impact -When contact time is shortest, the force of impact will be larger -The force is directly proportional to the change in momentumġ2 Relationship with impulsive force Impulsive force: So, the impulsive force is the rate of change of momentum Įxample: A bullet of mass 50 g is shot and it travels at a velocity of 100 m/s towards a target and takes 0.01 seconds to come to a stop. WINTER Template 11 CONCLUSION -The contact time on impact is affected by the hardness of surface. So, the change in momentum is: What happens to the force when the change of momentum is higher? 10 Relationship between force and change in momentum 09 Before After Is the egg experience any changes in momentum? RESULT & OBSERVATION 08 Surface types Contact time Observation on egg Force Table Longer / Shorter Break / Did not break Larger / Smaller Sponge Longer / Shorter Break / Did not break Larger / Smaller Relationship between contact time and force 07 Manipulated variables: ? Responding variables: ? Controlled variables:? WINTER Template 06 DESIGN AN EXPERIMENT What can we do to investigate the impulsive force? Materials: Eggs Newspapers Sponges LEARNING OUTCOMES Define impulse and impulsive force Explain the effects of increasing or decreasing time of impact on impulsive force Describe situations where an impulsive force is beneficial Solve problems involving impulsive force 03 WINTER Template 01 Are you ready to learn?
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