A thundercloud has a negative charge and an object on ground has a positive charge. Will the lightning discharge be from the cloud to the ground or from the ground to the cloud

What mass will a pumpkin have a force of 450 newton’s accelerates it to 110 m/s^2? include the correct units.

The ultracentrifuge is an important tool for separating and analyzing proteins. because of the enormous centripetal accelerations, the centrifuge must be carefully balanced, with each sample matched by a sample of identical mass on the opposite side. any difference in the masses of opposing samples creates a net force on the shaft of the rotor, potentially leading to a catastrophic failure of the apparatus. suppose a scientist makes a slight error in sample preparation and one sample has a mass 10 mg larger than the opposing sample. if the samples are 12 cm from the axis of the rotor and the ultracentrifuge spins at 70,000 rpm, what is the magnitude of the net force on the rotor due to the unbalanced samples? ( be thorough on your answer)

What is the coefficient of kinetic friction μk between the block and the tabletop?