Four student helpers push carts filled with textbooks. Each cart has the same mass, 25 kg. Each student pushes the cart with a different amount of force. Which cart has the least change in speed?

Which type of microscope would allow the viewer to see ribosomes inside a cell?

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?

Which of these metals are magnetic?