A student investigates the resistances of different wires. Plan an experiment to investigate the resistances of wires made from different metals. Resistance is calculated using the equation R = The following apparatus is available: ammeter voltmeter power supply metre rule a selection of wires made from different metals, You can also use other apparatus and materials that are usually available in a school laboratory. In your plan, you should: write a list of suitable metals for the wires you will investigate draw a diagram of a suitable electrical circuit using standard electrical symbols explain briefly how to carry out the investigation state the key variables to keep constant

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

At an oceanside nuclear power plant, seawater is used as part of the cooling system. this raises the temperature of the water that is discharged back into the ocean. the amount that the water temperature is raised has a uniform distribution over the interval from 10° to 25° c. what is the standard deviation of the temperature increase?

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)