(c) nail tips exert tremendous pressures when they are hit by hammers because they exert a large force over a small area. what force must be exerted on a nail with a circular tip of 1.00 mm diameter to create a pressure of 3.00 × 10 9 n/m 2 ? first calculate the area of the circular tip, express it in 10 -6 m2. for example, if the area is 0.68 = 6.8 × 10-6 m2, enter just 6.8.

What happens in a global convection cell

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

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)