Final answer:
To increase the distance a block travels when hit by a pendulum bob, the height from which the bob is dropped should be increased. This raises the potential energy, which upon release, becomes kinetic energy that can push the block farther.
Step-by-step explanation:
To increase the distance that the block travelled, the boys could perform an additional trial where they increase the height from which the bob is dropped (Option A). According to the formula for potential energy (PE = mgh), increasing the height (h) at which the pendulum bob is dropped will increase the bob's potential energy. When the bob is released, this increased potential energy will convert to kinetic energy, which can translate to a greater distance traveled when it impacts the block. Changing the string length, orientation of the block, or material of the bob would not necessarily increase the distance traveled without further context.
The potential energy (PE) of the ball when it has fallen 3 m, with mass m and acceleration due to gravity g, is calculated using PE = mgh. If a ball rolls down a 15 m hill, its gravitational potential energy at the top can also be calculated with this formula, and its velocity at the bottom can be found recognizing that the potential energy converts into kinetic energy. Similarly, using the principle of conservation of mechanical energy to find the height a bullet reaches involves equating the kinetic energy at the muzzle to the potential energy at the peak height it reaches, using the equation KE_initial = PE_final, where KE is ½mv² and PE is mgh.