4.2.5 Quiz: Time for Anaerobics Question 2 of 5
During an anaerobic burst of exercise, what percentage of a person's
maximum heart rate should be reached?
A. 60-70%
B. 80-90%
C. 70-80%
D. 90-100%
UBMIT
The answer should be D 90-100%

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

What object a collides with object b and bounces back its final momentum is?