To answer the above questions, Newton's second law of motion (F net = m In situations in which there is air resistance, why do more massive objects fall faster than less massive objects?.Why do objects that encounter air resistance ultimately reach a terminal velocity?.In particular, two questions will be explored: In addition to an exploration of free fall, the motion of objects that encounter air resistance will also be analyzed. because the air resistance is the same for each? Why? These questions will be explored in this section of Lesson 3. But why do all objects free fall at the same rate of acceleration regardless of their mass? Is it because they all weigh the same?. This particular acceleration value is so important in physics that it has its own peculiar name - the acceleration of gravity - and its own peculiar symbol - g. Also, find the magnitude of the force exerted on the object.In a previous unit, it was stated that all objects ( regardless of their mass) free fall with the same acceleration - 9.8 m/s/s. Calculate the initial and final momentum of the object. ![]() Calculate the force exerted by the brakes on the motorcar if its mass along with the passengers is 1000 kg.Īn object of mass 100 kg is accelerated uniformly from a velocity of 5 m s–1 to 8 m s–1 in 6 s. Now, if the force was applied for a duration of 5 s, what would be the final velocity of the object?Ī motorcar is moving with a velocity of 108 km/h and it takes 4 s to stop after the brakes are applied. It increases the object’s velocity from 3 m s This high unbalanced force breaks the bricksĪ constant force acts on an object of mass 5 kg for a duration of 2 s. Since in this case, karate player takes very less time, there Is very high rate of change in momentum and hence high unbalanced force ![]() ![]() Hence a large amount of change in momentum obtained in very short span of time The hands of karate player moves very fast When the hands touch the ice,the velocity is brought down to 0 When hands of karate player move, they carry velocity It is due to very high amount of momentum produced in a very short span of time How a karate player breaks slab of bricks in single blow The seat belts worn by the passengers increase the time taken by the passengers to fall forward.ĭue to longer time, the rate of change of momentum is reduced. In a car accident, a fast running car stops suddenly.ĭue to this, the large momentum of the car reduces to zero in a very short time. The rate of change of momentum of the athlete is less due to which a smaller stopping force acts on the athlete. When the athlete falls on a cushion or a heap of sand, then the jumper takes a longer time to come to rest. Why a high jumper is provided cushion or heap of sand on fallingĪ cushion or a heap of sand is provided to prevent injury to the athlete when he falls down after making a high jump. Hence applied force decreases if fielder moves backwards Suppose fielder moves back and catches this ball in 3 seconds,įorce = Change in Momentum/Time = 6/3 = 2 Suppose fielder catches this ball in 2 seconds,įorce = Change in Momentum/Time = 6/2 = 3 When fielder catches ball, ball stops moving and velocity becomes 0Ĭhange in Momentum = Mass * (New Velocity - Old Velocity) Suppose ball was moving at speed of 10 meters/second Suppose weight of ball was 600 grams = 0.6 kg If he moves back, he increases the time due to less force on players hand and he is not hurt If fielder catches ball suddenly, it will take less time and hence there will be more force of ball on players hand which may hurt the fielder (Hence force is inversely propirtional to time, More the time less the force and less the time more the force) This means that there is very high change in momentum when the fielder catches a ballįorce = Change in Momentum/Time = m (v - u)/t ![]() When a fielder catches a moving ball, it actually brings velocity of ball to 0 in very short span of time This reduces the rate of CHANGE of momentum and applied force He does it to increase the amount of time while catching a ball. Why a fielder pulls his hands backwards while fielding the ball
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