Which of these statements correctly describes a key difference between aerobic activity and anaerobic activity? A: Aerobic activity is intense and of short duration, while anaerobic activity involves moderate effort over a long period of time.
B: Muscles do not use oxygen during aerobic activity, but they do during anaerobic activity.
C: Aerobic activity increases muscle endurance, while anaerobic activity increases muscle strength.
D: Lifting weights is aerobic activity, while jogging is an anaerobic activity.

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

Both speed and velocity measure how fast something is moving. however, since speed is not a it does not require a(n question 6 options: a) quantity , unit b) magnitude, unit c) scalar, direction d) vector, direction