Question

4.A brick of concrete weighs 98 N when placed on a scale on the floor of a physics laboratory. When the same brick is placed on an identical scale placed at the bottom of a pool of water, it weighs 49 N. Explain fully why this is so.

5.When a 50 g mass is placed at the end of a certain spring, the period of oscillation is measured to be 0.442 s. When a 250 g mass is placed on the same spring, how will the period change i.e., remain the same, increase or decrease? Explain your answer.

6.A 2.533 kg mass sits on a spring (k = 100 N/m) that is attached to a driver that can drive oscillations in the mass-spring system. As the driving frequency is changed, the amplitude of the resulting oscillations changes. Under what condition does resonance occur?

Answer 1

Due to force of buoyancy in liquid net force vertically downward decreases that's why weight if the brick reduced form 98 n to 49 N. Force of buoyancy works vertically upward reducing weight of the brick. PLEASE upvote the answer and provide feedback