Answer to Question 7

Spring constant = 3920 N ÷ 0.05 m = 78400 N m^{-1} (see Q4). E = 1/2 ke^{2} = 0.5 × 78400 N m^{-1} × (0.05 m)^{2} E = 98 J Did you forget to divide by 4?

Spring constant = 3920 N ÷ 0.05 m = 78400 N m^{-1}

(see Q4).

E = 1/2 ke^{2} = 0.5 × 78400 N m^{-1} × (0.05 m)^{2}

E = 98 J

Did you forget to divide by 4?