In the olympiad of 708 b. c. some athletes competing in the standing long jump used handheld weights called halteres to lengthen their jumps. the weights were swung up in front just before liftoff and then swung down and thrown backward during the flight. suppose a modern 80 kg long jumper similarly uses two 5.80 kg halteres, throwing them horizontally to the rear at his maximum height such that their horizontal velocity is zero relative to the ground. let his liftoff velocity be vector v = (9.5i hat + 4.0j) m/s with or without the halteres, and assume that he lands at the liftoff level. what distance would the use of the halteres add to his range?

Which statement correctly describes a step-up transformer? a. it increases the amount of electric energy available. b. it increases the voltage of an electric current. c. it changes direct current into alternating current. d. it has more loops of wire in its primary coil.

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 ⇒

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.