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2 years ago

15

When you push on a stationary object on a horizontal surface and it doesn't move, what kind of force is most likely opposing you

r efforts

1 answer:

quester [9]2 years ago

4 0

Frictional force causes resistance

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Information travels at 120 metres per second in neurones. Calculate the time it would take for the information to travel 2.3 m a

Klio2033 [76]

Answer:

5 remainder 5

Explanation:

divide 120 by 2.3

4 0

3 years ago

A 200 kg weather rocket is loaded with 100 kg of fuel and fired straight up. It accelerates upward at 30 m/s2 for 35 s , then ru

Gre4nikov [31]

Answer:

a) $h_m=74625\ m$

b) $t=265.55\ s$

Explanation:

Given:

mass of rocket, $m_r=200\ kg$

mass of fuel, $m_f=100\ kg$

acceleration of the rocket consuming fuel, $a=30\ m.s^{-2}$

time after which the fuel exhaust, $t_f=35\ s$

<u>During the phase of fuel exhaustion:</u>

<u>velocity attained by the rocket just as the fuel ends:</u>

$v_f=u+a.t_f$

where:

$u=$ initial velocity of the rocket = 0

$v_f=0+30\times 35$

$v_f=1050\ m.s^{-1}$ this will be the initial velocity for the phase of ascending of the rocket's height under the influence of gravity.

<u>height at which the fuel finishes:</u>

$v_f^2=u^2+2a.h_f$

$1050^2=0^2+2\times 30\times h_f$

$h_f=18375\ m$

<u>During the phase of ascend in height of rocket after the fuel is over:</u>

<u>Time taken to reach the top height after the fuel is over:</u>

$v=v_f+g.t'$

at top v = (final velocity during this course of motion )= 0 $m.s^{-1}$

$0=1050-9.8\times t'$

$t'=107.1429\ s$

<u>Height ascended by the rocket after the fuel is over:</u>

$v^2=v_f^2+2g.h'$

at the top height the velocity is zero

$0^2=1050^2-2\times 9.8\times h'$ (-ve sign denotes that the direction of motion is opposite to that of acceleration)

$h'=56250\ m$

<u>Therefore the maximum altitude attained by the rocket:</u>

$h_m=h_f+h'$

$h_m=18375+56250$

$h_m=74625\ m$

b)

time taken by the rocket to fall back to the earth:

$h_m=v.t_m+\frac{1}{2} g.t_m^2$

where:

$v=$ initial velocity of the rocket during the course of free fall from the top height.

$74625=0+4.9\times t_m^2$

$t_m=123.41\ s$

Now the total time for which the rocket is in the air:

$t=t_f+t'+t_m$

$t=35+107.1429+123.41$

$t=265.55\ s$

4 0

3 years ago

Si: A + B = C – D es una ecuación física donde A, B, C y D son magnitudes físicas entonces [ A ] = [ B ] = [ C ] = [ D ]

PilotLPTM [1.2K]

Answer:

$[A] = [B] = [C] = [D]$ por el Principio de Homogeneidad Dimensional y el uso de operaciones de adición y sustracción.

Explanation:

Por el Principio de Homogeneidad Dimensional, A, B, C y D deben tener las mismas magnitudes físicas para la realización de operaciones de adición y sustracción. Es decir:

$[A] + [B] = [C] - [D]$ , donde $[A] = [B] = [C] = [D]$

8 0

3 years ago

Andy pushes a box to the right with 5 N of force. Kristen pushes the box to the left with 3 N of force. What will be the resulti

REY [17]

The forces are applied in opposite direction.
So the net force will be the difference of both forces.
net force =5-3=2N

This force will be in direction of 5N(bigger force) means in direction which Andy is pushing.

6 0

3 years ago

Radio devices are used for communication in space. Why

Elena-2011 [213]

Because radio waves can travel in space but sound waves cannot.

6 0

3 years ago