The height of a tree is 4 m.

An electron of mass 9.11 1031 kg has an initial speed of 3.00 105 m/s. It travels in a straight line, and its speed increases to

elena55 [62]

Explanation:

It is given that,

Mass of an electron, $m=9.11\times 10^{-31}\ kg$

Initial speed of the electron, $u=3\times 10^5\ m/s$

Final speed of the electron, $v=7\times 10^5\ m/s$

Distance, d = 5 cm = 0.05 m

(a) The acceleration of the electron is calculated using the third equation of motion as :

$a=\dfrac{v^2-u^2}{2d}$

$a=\dfrac{(7\times 10^5)^2-(3\times 10^5)^2}{2\times 0.05}$

$a=4\times 10^{12}\ m/s^2$

Force exerted on the electron is given by :

$F=m\times a$

$F=9.11\times 10^{-31}\times 4\times 10^{12}$

$F=3.64\times 10^{-18}\ N$

(b) Let W is the weight of the electron. It can be calculated as :

$W=mg$

$W=9.11\times 10^{-31}\times 9.8$

$W=8.92\times 10^{-30}\ N$

Comparison,

$\dfrac{F}{W}=\dfrac{3.64\times 10^{-18}}{8.92\times 10^{-30}}$

$\dfrac{F}{W}=4.08\times 10^{11}$

Hence, this is the required solution.

8 0

3 years ago

Bolt starts the race not moving, but then increased his speed until he reaches a top speed. Once Bolt reaches his top speed he m

LekaFEV [45]

Answer:

a

Explanation:

In order to maintain speed, a moving object or person must move at a constant velocity. Accelerating will increase the speed while decelerating will reduce the speed.

Hence, for Bolt to be able to maintain the top speed for a few seconds, he needs to move at a constant velocity.

The correct option is a.

7 0

2 years ago

3. Take sugar, oil, corn syrup, a glass and water. Pour the water in the glass and then add each of the above the substances one

hoa [83]

Here are the observations

Sugar:-

Sugar is soluble in water
so It will dissolve in water .

Corn syrup:-

Corn syrup is also basically a sugar.
It will dissolve in water too .
If we shake the mixture in glass then corn syrup will be dissolved.

Oil:-

Oil is not soluble in water
Hence it won't dissolve in water.
It will float over water and make two layers

7 0

2 years ago

Two scientists are discussing their beliefs about something they cannot observe

svetoff [14.1K]

Could it be hypothesis?

5 0

3 years ago

Read 2 more answers

Why is it important foe scientists to know how many valence electrons a given element has

Vikentia [17]

Because the number of valence electrons of an element determines the properties and in particular the reactivity of that element.

In fact, elements of the first group (i.e. only one valence electron) have high reactivity, because they can easily give away their valence electron to atoms of other elements forming bonds. On the contrary, elements of the 8th group (noble gases) have their outermost shell completely filled with electrons, so they do not have valence electrons, and they have little or no reactivity at all.

3 0

3 years ago