Answer:
A 3 feet radius snowball will melt in 54 hours.
Explanation:
As we can assume that the rate of snowball takes to melt is proportional to the surface area, then the rate for a 3 feet radius will be:
T= A(3 ft)/A(1 ft) * 6 hr
A is the area of the snowballs. For a spherical geometry is computing as:
A=4.pi.R^2
Then dividing the areas:
A(3 feet)/A(1 foot) = (4 pi (3 ft)^2)/(4 pi (1 ft)^2) = (36pi ft^2)/(4pi ft^2)= 9
Finally, the rate for the 3 feet radius snowball is:
T= 9 * 6 hr = 54 hr
Answer: 16N
Explanation:
Given that:
mass of box M= 2 kg
Initial speed V1 = 4 m/s
Final speed V2 = 8 m/s
Time taken T= 0.5 s
Average strength of this force F = ?
Now, recall that Force is the rate of change of momentum per unit time
i.e Force = momentum / time
Hence, F = M x (V2 - V1)/T
F = 2kg x (8 m/s - 4 m/s) / 0.5s
F = 2kg x (4 m/s / 0.5s)
F = 2kg x 8 m/s/s)
F = 16N
Thus, the average strength of this
force is 16 newton.
Answer: Electric field vector is created by an electric force of a charged particle.
Explanation: The direction of the field vector can be determined by applying Coulomb’s Law which explains the electric force between charge particles. If q is positive the force is repulsive, to a test charge ( which is positive always ) and if q is negative the force is attractive to a test charge.
Answer:
A: They produce a real image.
Explanation:
The images formed on the retina of the eye for a normal visibility must always be real.
Only a real image can be physically projected on any physical object whereas the virtual images are visible due to reflections.
- The nearsightedness is corrected with the help of a concave lens since it is the condition of the eye lens remaining thick and curved to converge the rays entering the eyes after a shorter distance which results in their image formation even before the retinal surface so to initially diverge them a bit so that they converge on the retinal surface and form the image there we use concave lens. Vice-versa of the above justification in the case of farsightedness.
Answer:
When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.
