If an equation is dimensionally correct, it does not mean that the equation must be true. On the other hand, when the equation is dimensionally correct, the equation cannot be true. Dimensional analysis is a technique used to check whether a relationship is correct
Answer:
Option c) are perpendicular to the electric field
Explanation:
Equipotential surfaces are perpendicular to the electric field. the electric field lines are projected outwards from the equipotential surface, i.e., the lines of the electric field are at 90 to the equipotential surface.
Equipotential surface are those surfaces that have the same potential at any point on the surface. Thus the potential difference at any point on the surface is zero due to same potential.
Any charge particle on this surface will move in a perpendicular direction to the Coulombian force. No work is done by the force on a particle moving on an equipotential surface.
The object D is made up of material Lead. The correct option is D.
<h3>What is specific heat?</h3>
The specific heat is the amount of heat required to change the temperature by 1°C. It is denoted by C.
Two 1-kg objects, C and D, increase in temperature by the same amount, but the thermal energy transfer of object C is greater than the thermal energy transfer of object D. The object C has a specific heat of 235 J/kg-K.
Q = m C ΔT
Qc > Qd
The energy transfer is proportional to specific heat.
Specific heat of D must be less. The possible material with specific heat less than the given value is for Lead material.
Thus, the correct option is D.
Learn more about specific heat,
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Answer:
-
Explanation:
We are given that
Mass of cars= m=1900 kg
Initial speed of car=u=20 m/s
Final speed of car=v=0
Time==1.3 s
We have to find the average force exerted on the car.
Average force=
Hence, the average force exerted on the car that hits a line of water barrels=-
Answer:
0.799 m/s if air resistance is negligible.
Explanation:
For how long is the ball in the air?
Acceleration is constant. The change in the ball's height depends on the square of the time:
,
where
- is the change in the ball's height.
- is the acceleration due to gravity.
- is the time for which the ball is in the air.
- is the initial vertical velocity of the ball.
- The height of the ball decreases, so this value should be the opposite of the height of the table relative to the ground. .
- Gravity pulls objects toward the earth, so is also negative. near the surface of the earth.
- Assume that the table is flat. The vertical velocity of the ball will be zero until it falls off the edge. As a result, .
Solve for .
;
;
;
.
What's the initial horizontal velocity of the ball?
- Horizontal displacement of the ball: ;
- Time taken:
Assume that air resistance is negligible. Only gravity is acting on the ball when it falls from the tabletop. The horizontal velocity of the ball will not change while the ball is in the air. In other words, the ball will move away from the table at the same speed at which it rolls towards the edge.
.
Both values from the question come with 3 significant figures. Keep more significant figures than that during the calculation and round the final result to the same number of significant figures.