[ s = v \cdot t = 5 , \textm/s \times 20 , \texts = 100 , \textm ] 2. Force (Sila) Key formula: ( F = m \cdot a ) (Newton’s second law) Unit: Newton (N) Weight: ( F_g = m \cdot g ) (( g \approx 9.81 , \textN/kg ), often taken as ( 10 , \textN/kg ) in 7th grade) Problem 3 What is the weight of a 5 kg object? (Use ( g = 10 , \textN/kg ))
[ m = \rho \cdot V = 7800 , \textkg/m^3 \times 0.05 , \textm^3 = 390 , \textkg ] 4. Pressure (Tlak) Key formula: ( p = \fracFA ) Unit: Pascal (Pa) = ( \textN/m^2 ) Pressure in liquids: ( p = \rho \cdot g \cdot h ) Problem 7 A 500 N weight stands on a box with base area 0.25 m². What pressure does it exert? fizika 7 razred zadaci i rješenja
[ F_g = m \cdot g = 5 , \textkg \times 10 , \textN/kg = 50 , \textN ] Problem 4 A force of 20 N acts on a 4 kg object. What is its acceleration? [ s = v \cdot t = 5