A train rolls at a constant speed of 10 m/s across a horizontal track. A child standing on the flatbed of the train throws a ball so that it appears to move straight up to an observer standing next to the track. a) What is the horizontal speed of the ball relative to the observer?

b) What is the horizontal speed of the ball relative to the train?

C)If the ball is also thrown upward with a speed of 20 m/s, what is the overall Initial speed of the ball
relative to the train?

Which statement best describes resistance? resistance is a. how well a current will flow in a material and is measured in volts. b. how well a material conducts an electrical charge and is measured in ohms. c. the ability of a material to attract a positive charge to create a current. d. the ability of a material to repel neutral charges and is measured in ohms.

Janelle made a hypothesis bout the uneven temperatures inside her house during winter. she believes that 50% of the ducts are blocked and she plans to investigate. if she wants to prove her hypothesis using scientific processes what should she do next?

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.