A 160.0 km long electric power line made out of copper is installed during the Spring months at an average temperature of 10.2 °C.
1) What is the change in the length of the power line on a hot summer day, when the temperature is 32.1 °C? The coefficient of linear expansion for copper is 1.62×10^(-5) 1/C°. Use a positive sign for an increase in length and negative for a decrease.
2) What is the change in the length of the cable on a -28.7 °C cold Winter day?

Determine the amount of work done when a crane lifts a 100-n block form 2m above the ground to 6m above the ground

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 ⇒

Acar starts from rest at a stop sign and reaches a velocity of 25 m/s w in 4 seconds. determine the acceleration of the car. question 3 options: a) 6,25 m/s2 b)6.25 m/s c)100 m/s2 d)100 m/s