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3 years ago

See The Picture And Anwser

Physics

2 answers:

pantera1 [17]3 years ago

8 0

Answer:

$from \: first \: equation \: of \: motion \\ v = u + at \\ a = \frac{v - u}{t} \\ a = \frac{15 - 24}{12} \\ a = - 0.75 \: {ms}^{ - 2}$

Ratling [72]3 years ago

7 0

Answer:

a = -0.75 m/s^-2

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An overnight rainstorm has caused a major roadblock. Three massive rocks of mass m1=528 kg, m2=838 kg and m3=311 kg have blocked

JulsSmile [24]

Answer:

$FA=419,25N$

$F12=287,25N$

Explanation:

The bulldozer is moving the rocks as one system, the weigth for the complete system is:

$M=m1+m2+m3=1677kg$

From newton´s second law the acceleration can be related to the force by:

$FA=m*a=1677kg*0,250m/s^{2}=419,25N$

on the middle rock we have the force F12 from the first to the middle rock on the direction of movement and F32 from the las rock to the middle rock on the opposite direction of movement.

For the last rock to accelerate at the same rate it must be subjected to a force:

$F23=m3*a=311kg*0,250m/s^{2} =77,75N$

This equals the force F32 on the opposite direction. the resultant force on the middle rock to mantain this acceleration should be:

$F2=m2*a=838kg*0,250m/s^{2} =209,5N$

The sum of all the forces applied to the middle rock is:

$F2=F12-F32$

Solving for F12:

$F12=F2+F32=209,5N+77,75N=287,25N$

3 0

3 years ago

The stoplight had just changed and a 2100 kg Cadillac had entered the intersection, heading north at 3.2 m/s , when it was struc

elena55 [62]

Explanation:

It is given that,

Mass of the Cadillac, $m_1=2100\ kg$

Speed of Cadillac, $v_1=3.2\ m/s$ (towards north)

Mass of Volkswagen, $m_2=1100\ kg$

The cars stuck together and slid to a halt, leaving skid marks angled 35 degrees north of east.

According to the law of conservation of momentum,

The momentum along x axis, $m_1v_1=(m_1+m_2)\ usin35$ ............(1)

The momentum along y axis, $m_2v_2=(m_1+m_2)\ ucos35$ ...........(2)

From equation (1) and (2) it is clear that,

$\dfrac{m_1v_1}{m_2v_2}=tan35$

$v_2=\dfrac{m_1v_1}{m_2\ tan35}$

$v_2=\dfrac{2100\times 3.2}{1100\times \ tan35}$

$v_2=8.72\ m/s$

So, the Volkswagen going just before the impact is 8.72 m/s. Hence, this is the required solution.

6 0

3 years ago

A single conservative force F = (7.0x - 11) N, where x is in meters, acts on a particle moving along an x axis. The potential en

Umnica [9.8K]

Answer:

(a) 34.6429J

(b) -1.57 m

Explanation:

The derivative of the potential energy with respect to the position is equal to the negative of the force, so:

$-\frac{dU}{dx}=F\\ dU=-Fdx$

Then, if we integer both sides, we get:

∫dU = -∫(7x - 11)dx

$U=\frac{-7}{2}x^{2} + 11x + c$

we know that U is equal to 26 J when x is zero, so:

$U=\frac{-7}{2}x^{2} + 11x + c$

$26=\frac{-7}{2}(0)^{2} + 11(0) + c$

$26=c$

Finally, the equation for the potential energy is:

$U(x)=\frac{-7}{2}x^{2} + 11x + 26$

Therefore, the maximum positive potential energy is the energy when x is equal to 11/7. That is because the equation of U is the equation of a parable, and the vertex in a parable is given by:

$x=\frac{-b}{2a} = \frac{-11}{2(-7/2)} =\frac{11}{7}$

Where b is the number beside x and a is the number beside $x^{2}$ , Then, the value of maximum U is:

$U(11/7)=\frac{-7}{2}(11/7)^{2} + 11(11/7) + 26$

$U(11/7)=34.6429J$

On the other hand, the negative and positive values of x where the potential energy is equal to zero is calculated as:

$U(x)=\frac{-7}{2}x^{2} + 11x + 26$

$0=\frac{-7}{2}x^{2} + 11x + 26$

if we solve this using the quadratic equation, we get:

$x =\frac{-11+\sqrt{11^{2}-4(-7/2)(26)} }{2(-7/2)}=-1.5747$

$x =\frac{-11-\sqrt{11^{2}-4(-7/2)(26)} }{2(-7/2)}=4.7175$

Finally, the negative and positive values of x where the potential energy is equal to zero are -1.5747 and 4.7175 respectively.

3 0

3 years ago

How the energy affects the speed of the particles in a substance

Daniel [21]

Increases

Explanation:

Energy increases the speed of the particles in a substance. When energy is added to a substance they gain more kinetic to move.

When energy is added to solid, the particles begins to vibrate about their fixed point.
They reach a point where they break lose and the ordered structure of a typical solid collapses.
They begin to move about freely and flow as in a liquid.
When enough energy is added, they break their intermolecular attractions and becomes gaseous.
An increase in energy increases the kinetic energy of the particles of a substance.
The reverse is the case when energy is removed.

Learn more:

Kinetic energy brainly.com/question/6536722

#learnwithBrainly

4 0

4 years ago

How many electrons must be removed from a neutral, isolated conducting sphere to give it a positive charge of 8.0 x 10 8 C? [Q=n

Solnce55 [7]

Answer: the ball will have a charge of 8x10^8C when we remove 5x10^27 electrons.

Explanation:

If the sphere is neutral, then the charge of the sphere is 0C

Now, when we remove an electron (-1.6*10^-19 C) we are subtracting a negative number, so the new charge of the sphere is: 1.6*10^-19 C

Now, for N removed electrons, the charge of the sphere is:

N*1.6*10^-19 C

We want to find the number N when:

N*1.6*10^-19 C = 8.0x 10^8 C

N = (8.0/1.6)x10^(8 + 19) = 5x10^27 electrons.

7 0

3 years ago