Physics
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During a warm-up in a velodrome, Charles, an inattentive cyclist moving at a velocity of 12 m/s Î collides with Albert, moving at a velocity of -10 m/s Î. Charles and Albert and their bikes become entangled and begin to slide together on the horizontal floor. The friction coefficient between the cyclists-bikes system and the velodrome is 0.15. Find the direction of motion after the collision and the distance traveled on the floor until they stop. The combined mass of Charles and his bike is 72 kg and for Albert and his bike is 70 kg.
Scientists have calculated that for a particular distant massive solid planet, every couple of million years, a 1.0-km-diameter planetoid crashes into it. One such planetoid having a density of 4300 kg per cubic meter, is moving toward the planet at a speed of 25 km/s. Assuming the planetoid to be spherical, evaluate the destructive energy that will be released after it collides with the planet.
A 4.1 x 105 kg satellite is heading toward another satellite in space. The former satellite's speed needs to be changed by 0.50 cm/s to avoid a collision. The thrusters onboard can exert a constant force of 3.2 N. Calculate the time for which this force must act on the former satellite to change its course sufficiently.
Calculate the average force exerted on the ball by the racket during contact when a 0.146-kg tennis ball, served horizontally at 33.0 m/s, hits the racket and is lobbed straight up to a height of 31.6 m, with the contact duration between the racket and the ball assumed to be 2.6 ms.
The impact resistance of new motorcycle helmets is tested by striking them against rigid barriers at a speed of 20 m/s. A prototype helmet, weighing 2 kg, comes to a complete stop in 0.2 seconds upon impact. Determine the average force exerted on the helmet by the barrier during the collision.
In crash tests for new electric scooter models, scooters are subjected to controlled collisions with solid barriers at a velocity of 10 m/s. A prototype scooter, with a mass of 80 kg, takes 0.4 seconds from impact until it comes to a complete stop. Determine the average deceleration experienced by the scooter in terms of "g's".