A man is walking with a speed of 1.0 m/s (relative to the ground) on a sidewalk when a child running with a speed of 3 m/s (relative to the ground) comes toward him. What is the speed of the child relative to the man?

An object with initial temperature 130 ∘ f is submerged in large tank of water whose temperature is 50 ∘ f . find a formula for f ( t ) , the temperature of the object after t minutes, if the cooling constant is k = − 0.2 . remember newton's law of cooling (the rate of change of temperature with respect to time is equal to k times the difference between the temperature of the object and the surrounding temperature) ! : )