The question asks about the direction of the force of friction relative to the direction of motion of an object. Understanding the fundamental nature of friction as a resistive force is key to answering this question.
A) Opposite to the direction of motion. This is the defining characteristic of frictional force. It always acts in a direction that opposes the relative motion or tendency of motion between the surfaces in contact.
The question asks us to identify the correct statements regarding the consequences if the phenomenon of capillarity did not exist. We need to evaluate each statement based on our understanding of capillarity.
Based on the analysis, statements 1, 3, and 4 are correct.
B) 1, 3 and 4 only
The question asks to identify the correct statements regarding the state of motion of an object. We need to evaluate each statement based on fundamental physics principles related to motion and rest.
D) (i), (ii) and (iii) — All three statements are correct. The state of motion is defined by velocity (speed and direction). Rest is a state of zero speed and is considered a state of motion.
The question asks about the effect of friction on an object, given that friction acts in the opposite direction of motion. We need to understand how a force acting opposite to motion influences an object's speed and state of motion.
Correct Option: D) Slows down and stops
The problem asks for the work done by a force that changes the speed of an object. This can be solved using the Work-Energy Theorem, which states that the net work done on an object is equal to the change in its kinetic energy.
The formula for kinetic energy is \(KE = \frac{1}{2}mv^2\).
\[ KE_i = \frac{1}{2}mu^2 \]\[ KE_i = \frac{1}{2} (1.0 \, \text{kg}) (4 \, \text{m/s})^2 \]\[ KE_i = \frac{1}{2} (1.0 \, \text{kg}) (16 \, \text{m}^2/\text{s}^2) \]\[ KE_i = 8 \, \text{J} \]The work done (\(W\)) by the force is equal to the change in kinetic energy.
\[ W = \Delta KE = KE_f - KE_i \]\[ W = 32 \, \text{J} - 8 \, \text{J} \]\[ W = 24 \, \text{J} \]C) 24J is the correct answer. The work done by the force is the change in the object's kinetic energy, which is \(32 \, \text{J} - 8 \, \text{J} = 24 \, \text{J}\).
The question asks for the definition of pressure. Pressure is a fundamental concept in physics, defined as the force applied perpendicular to a surface divided by the area over which that force is distributed.
Correct Option: B) force / area on which it acts
This option accurately represents the definition of pressure, which is the force applied perpendicular to a surface divided by the area over which the force is distributed. The unit of pressure in the SI system is the Pascal (Pa), which is equivalent to one Newton per square meter (\(N/m^2\)).