A car travels 60 km in 1 hour, 100 km in 2 hours, and then 40 km in 1 hour before reaching its destination. What was the car's average speed? A. 30 km/h
B. 40 km/h
C. 50 km/h
D. 75 km/h

25pts the diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.

A10nc charge sits at a point in space where the magnitude of the electric field is 1500 n/c. what will the magnitude of the field be if the 10 nc charge is replaced by a 20 nc charge? assume the system is big enough to consider the charges as small test charges.