Answer:
Heat is always the transfer of energy from an object at a higher temperature to an object at a lower temperature.
Explanation:
i would choose steel because the steel used for normal construction have several hundred Mega Pascal strength. one of the special feature of steel is its ductility. it is the deformation capability before the final breakage.
Answer:
Force of static friction between the two surfaces
Explanation:
When two surfaces come into contact, they exert a force that resist the sliding of the two surfaces. This force is called static friction.
This force is given by the relation
Where,
μ - coefficient of static friction
η - normal force acting on the body
When a force acts on a body placed on a rough surface, it doesn't do any work if the applied force was less than the force of static friction.
So, in order to move the body, the applied force should be greater than the force of static friction.
Answer:
The ball travels a distance of 20 m in the time interval of 4 s
Explanation:
Using s = ut + 1/2at² where s = distance travelled by the ball, u = initial velocity of ball = 0 m/s (since it starts from rest), a = acceleration of the ball = 2.50 m/s² and t = time = 4 s.
Substituting the variables into the equation, we have
s = ut + 1/2at²
s = 0 × 4 s + 1/2 × 2.50 m/s² × (4 s)²
s = 0 + 1/2 × 2.50 m/s² × 16 s²
s = 1/2 × 40 m
s = 20 m
So, the ball travels a distance of 20 m in the time interval of 4 s.
Answer:
D) The velocity of the airplane must be greater than the speed of sound
Explanation:
Sonic boom is a phenomenon that occurs when an airplane travels ay a velocity greater than the speed of sound.
When this condition is met, the sound waves produced by the airplane (mainly from the engine) is not able to travel ahead of the plane, because the plane is moving at a greater speed than the sound itself; as a result, it is only transmitted behind the plane.
In this situation, a shock wave is produced. This shock wave is associated with a very loud "bang", that can be heard clearly even at several kilometers distance (in fact, supersonic planes are normally not allowed to fly over residential areas. In the past, for example the Concorde, was only allowerd to fly at supersonic speed over the ocean).
So the correct answer is
D) The velocity of the airplane must be greater than the speed of sound
