18)

An observer on Earth sees rocket 1 leave Earth and travel toward Planet X at 0.3c. The observer on Earth also sees that Planet X

Verizon [17]

Answer:

0.625 c

Explanation:

Relative speed of a body may be defined as the speed of one body with respect to some other or the speed of one body in comparison to the speed of second body.

In the context,

The relative speed of body 2 with respect to body 1 can be expressed as :

$u'=\frac{u-v}{1-\frac{uv}{c^2}}$

Speed of rocket 1 with respect to rocket 2 :

$u' = \frac{0.4 c- (-0.3 c)}{1-\frac{(0.4 c)(-0.3 c)}{c^2}}$

$u' = \frac{0.7 c}{1.12}$

$u'=0.625 c$

Therefore, the speed of rocket 1 according to an observer on rocket 2 is 0.625 c

5 0

3 years ago

How many excess electrons must be distributed uniformly within the volume of an isolated plastic sphere 25.0 cm in diameter to p

katrin [286]

Answer:

Required charge $q=2.6\times 10^{9}C$ .

$n=1.622\times 10^{10}\ electrons$

Explanation:

Given:

Diameter of the isolated plastic sphere = 25.0 cm

Magnitude of the Electric field = 1500 N/C

now

Electric field (E) is given as:

$E =\frac{kq}{r^2}$

where,

k = coulomb's constant = 9 × 10⁹ N

q = required charge

r = distance of the point from the charge where electric field is being measured

The value of r at the just outside of the sphere = $\frac{25.0}{2}=12.5cm=0.125m$

thus, according to the given data

$1500N/C=\frac{9\times 10^{9}N\times q}{(0.125m)^2}$

or

$q=\frac{0.125^2\times 1500}{9\times 10^{9}}$

or

Required charge $q=2.6\times 10^{9}C$ .

Now,

the number of electrons (n) required will be

$n=\frac{required\ charge}{charge\ of\ electron}$

or

$n=\frac{2.6\times 10^{-9}}{1.602\times 10^{-19}}$

or

$n=1.622\times 10^{10}\ electrons$

6 0

4 years ago

a body of mass 20kg initially at rest is subjected to a force of 40N for 1sec calculate the change in kinetic energy showing the

Tema [17]

Answer:

Change in KE is 40 J

Explanation:

Recall that the impulse exerted on an object equal the change of momentum of the object (ΔP), which in time is defined as the product of the force exerted on it times the time the force was acting:

Change in momentum is: ΔP = F * Δt

In our case,

ΔP = 40 N * 1 sec = 40 N s

Since the object was initially at rest, its initial momentum was zero, and the final momentum should then be 40 N s.

So, the initial KE was 0, and the final (KEf) can be calculated using:

KEf = 1 /(2 m) Pf^2 = 1 / (40) 40^2 = 40 J

So, the change in kinetic energy is:

KEf - KEi = 40 J - 0 j = 40 J

8 0

3 years ago

Help plss .. Two bicyclists are accelerating forward in a straight line, and Biker 1 has less

castortr0y [4]

Explanation:

Remember Newton's Second Law.

$F=ma$

If the force acting on both bikers is the same, we can look at the relationship between acceleration and mass.

If Biker 1 has a mass of 10kg and Biker 2 has a mass of 20kg, and both are being acted upon by a force of 100 N, let's see what that looks like. $100 = 10*a_1 \rightarrow a_1 = 100/10 = 10$

$100 = 20 *a_2 \rightarrow a_2 = 100/20 = 5$

So, given the same force, an object with GREATER mass will have less acceleration.

4 0

3 years ago

Describe Darwin’s<br> observations on the Galápagos islands<br> during his voyage on the HMS Beagle.

Helen [10]

Answer:

During the voyage Charles Darwin explored the Galapagos islands and noticed the same species have different adaptations in places. ... Charles noticed that each species has the same ancestor but they evolve to adapt over time so they can live longer.

Explanation:

4 0

3 years ago