Numa estrada seca, um carro com pneus em bom estado pode frear com desaceleração de \( 5 \mathrm{~m} / \mathrm{s}^{2} \). Se o carro estiver a \( 20 \mathrm{~m} / \mathrm{s} \), a distância mínima percorrida até parar vale, aproximadamente, em metros, é de: a) 100 b) 80 c) 50 d) 40 e) 25

A body weighs 3.1 N in air and 2.2 N when completely immersed in water of density \( 1000 \mathrm{~kg} / \mathrm{m}^{3} \). Calculate the volume of the body. Take the gravitational acceleration as \( 9.81 \mathrm{~m} / \mathrm{s}^{2} \).

Per la successiva lavorazione un laboratorio di oggettistica crea una lega di bronzo (densità \( 8,5 \mathrm{~g} / \mathrm{cm}^{3} \) ), composta principalmente di rame \( (\mathrm{Cu}) \) e arricchita con stagno (Sn), che possiede buone caratteristiche meccaniche ed è resistente alla corrosione. Sapendo che un oggetto di bronzo ha una massa di 1530 g , calcolane il volume.

Write what the core of transformer is. Explain the mutual induction process.

A straight wire carrying current placed perpendicular to a magnetic field is moved: (A) From strong magnetic flux density to weak magnetic flux density. (B) From weak magnetic flux density to strong magnetic flux density. (C) Due to the material of the straight wire. (D) Random motion doesn't depend on the magnetic flux density.

When a constant force acts upon an object, the acceleration of the object varies inversely with its mass. When a certain constant force acts upon an object with nass 4 kg , the acceleration of the object is \( 19 \mathrm{~m} / \mathrm{s}^{2} \). If the same force acts upon another object whose mass is 38 kg , what is this object's acceleration?