Answer:
a. Temperatures increase can change a solid to a liquid, but cannot change a liquid to a solid
b. The particles in a solid are much closer together than the particles in a liquid.
Explanation:
Any material expands when heated and contracts when cooled. So, when a body is heated to a particular temperature, it starts melting and changes into a liquid.
As the material expands the distance between the atoms or molecules increases and it will become a liquid. So it can move around the material. It doesn't become solid on further heating. But water is an exception where it contracts when heated from 0° to 4° C.
In solids, these atoms or molecules are closely packed. It is rigidly fixed.
The solid, as well as the liquid, has a definite volume, but the liquid does not have a definite shape.
Answer:
d. The buoyant force on the rock is constant as it sinks.
Explanation:
The sinking of an object in water can be explained by the Archimedes Principle.
The Archimedes principle states that the buoyant force on a submerged substance is equal to the water displaced by the submerging object. The buoyant force, however, does not change with depth as the substance sinks.
In the given question, when the rock moves beneath the pool, the buoyant force do not change and remains the same that is the amount of water displaced by rock remains the same.
Thus, Option-D is the correct answer.
Answer:
Explanation:
Given
mass of object
Object is attached to the ceiling of an elevator by a rope
Suppose T is the Tension in the rope so
acceleration of the elevator (upward)
From Free Body diagram we can write as
Speed = distance/time
Speed of car = 125 km/2 hours
Car speed = 62.5 km/hr.
Answer with Explanation:
The position of the particle as a function of time is given by
Part 1) The position as a function of time is shown in the below attached figure.
Part 2) By the definition of velocity we have
The velocity as a function of time is shown in the below attached figure.
Part 3) The displacement of the particle in the first 19 seconds is given by
Part 4) The distance covered in the first 19 seconds can be found by evaluating the integral
Part 4) As we can see that the position-time graph is parabolic in shape hence we conclude that the motion is uniformly accelerated motion.