Furthermore, is it possible to design a machine that has an efficiency greater than 100 %? In other words, no machine can be more than 100% efficient. Machines cannot multiply energy or work input. If a machine were 100% efficient then it can’t have any energy losses to friction, so no friction can be present.

Which requires more work- lifting a 50-kg sack a vertical distance of 2 m or lifting a 25-kg sack a vertical distance or 4 m? Both are the same amount of work because the force x distance is the same for each.

Bigger load: Work = (10 kg) x (9.8 m/s²) x (2 m) = 196 joules . Smaller load: Work = (5 kg) x (9.8 m/s²) x (4 m) = 196 joules. The work required is equal in both cases.

The work done is equivalent to energy. Therefore, the work can be compared to the kinetic energy. Since 109.89m J > 89.91m J, more work is required to increase the car’s speed from 50 mph to 60 mph.

Physics. What is the minimum energy needed to change the speed of a 1600 kg sport utility vehicle from 15.0 m/s to 40.0 m/s? 800*40^2 – 800*15^2 = 1,100,000 J.

Which statement is true if air resistance can be ignored? Both hit the ground at the same time. The one thrown at an angle hits the ground with a lower speed.

Top Answer Hence, 500kg object has more kinetic energy.

7.1 M/s

Power is the rate of doing work. In an inelastic collision an isolated system, the final total momentum is more than the initial momentum. Increasing a car’s speed from 0 to 30 mph or from 50 to 60 mph require the same amount of work. Air bags protect people by decreasing the change in momentum suffered during crashes.

So increasing from 0 to 30 mph will need an amount of energy scaled by 900 and increasing speed from 50 to 60 will need energy scaled by (3600–2500)=1100. So the second condition needs more energy.

At what point does the ball have the most energy? Ignore air resistance. At the highest point of its path.

So, the net force is 2496 N.

As the ball falls, that energy is converted to kinetic energy. When the ball collides with the floor, some of this kinetic energy is transferred to the floor and converted to thermal energy (friction) and elastic potential energy (ball deformation.)

Point E. As the ball falls from C to E, potential energy is converted to kinetic energy. The velocity of the ball increases as it falls, which means that the ball attains its greatest velocity, and thus its greatest kinetic energy, at E. 19.

However, some of its kinetic energy does become potential energy, and potential energy is at a maximum when the ball reaches its highest point.