A car moves north at a constant speed of 3 ms^-1 for 20 s and then east at a constant speed of 4ms^-1 for 20s. What is the average speed of the car during this motion?

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

Which accurately compares concave and convex lenses?

Describe cytokinesis in plants and animals. in animals: in plants.