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xxMikexx [17]
4 years ago
8

A 13,500 kg railroad freight car travels on a level track at a speed of 4.5 m/s. It collided and coupled with a 25,000 kg second

car, initially at rest and with brakes released. What is the speed of the two cars after collision
Physics
1 answer:
expeople1 [14]4 years ago
7 0

Answer: 1.6m/s

Explanation:

M1 = 13500kg

U1 = 4.5m/s

M2 = 25000kg

U2 = 0m/s (since the body is at rest)

V = ? (Common velocity or velocity after impact)

M1U1 + M2U2 = (M1 + M2)V

But U2 = 0

M1U1 = (M1 + M2)V

13500 * 4.5 = (13500 + 25000)v

60750 = 38500v

V = 60750 / 38500 = 1.5779 = 1.6m/s

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What current flows through a 2.56-cm-diameter rod of pure silicon that is 20.0 cm long, when 1.00 ✕ 103 V is applied to it? (Suc
vfiekz [6]

Answer:

Current, I = 0.0011 A

Explanation:

It is given that,

Diameter of rod, d = 2.56 cm

Radius of rod, r = 1.28 cm = 0.0128 m

The resistivity of the pure silicon, \rho=2300\ \Omega-m

Length of rod, l = 20 cm = 0.2 m

Voltage, V=1\times 10^3\ V

The resistivity of the rod is given by :

R=\rho\dfrac{L}{A}

R=2300\ \Omega-m\dfrac{0.2\ m}{\pi (0.0128\ m)^2}

R = 893692.30 ohms

Current flowing in the rod is calculated using Ohm's law as :

V = I R

I=\dfrac{V}{R}

I=\dfrac{10^3\ V}{893692.30\ \Omega}

I = 0.0011 A

So, the current flowing in the rod is 0.0011 A. Hence, this is the required solution.

6 0
3 years ago
Lexi is balancing equations. She is finding one equation to be very difficult to balance. Which explains how to balance the equa
Rina8888 [55]

Answer: ZnSO4 + Li2CO3 = ZnCO3 + Li2SO4 - Chemical Equation Balancer

Equation is already balanced.

Explanation: ZnSO4 + Li2CO3 = ZnCO3 + Li2SO4

6 0
3 years ago
In a lab, a student drags a shoe across the floor at constant speed. If the coefficient of static friction between the floor and
Svetllana [295]
<span>B) 0.6 N
   I suspect you have a minor error in your question. Claiming a coefficient of static friction of 0.30N is nonsensical. Putting the Newton there is incorrect. The figure of 0.25 for the coefficient of kinetic friction looks OK. So with that correction in mind, let's solve the problem. The coefficient of static friction is the multiplier to apply to the normal force in order to start the object moving. And the coefficient of kinetic friction (which is usually smaller than the coefficient of static friction) is the multiplied to the normal force in order to keep the object moving. You've been given a normal force of 2N, so you need to multiply the coefficient of static friction by that in order to get the amount of force it takes to start the shoe moving. So: 0.30 * 2N = 0.6N And if you look at your options, you'll see that option "B" matches exactly.</span>
7 0
3 years ago
Read 2 more answers
A basketball player shoots toward a basket 5.3 m away and 3.0 m above the floor. If the ball is released 1.9 m above the floor a
Snezhnost [94]

Answer:

Vi = 8.28 m/s

Explanation:

This problem is related to the projectile motion.

As we know there are two components of motion associated with this, the horizontal component and vertical component.

The horizontal distance covered by the ball is

Vx*t = x

Vx*t = 5.3

Vx = 5.3/t  eq. 1

Also we know that

Vx = Vicos(60)

Vx = Vi*0.5  eq. 2

equate eq. 1 and eq. 2

5.3/t = Vi*0.5

5.3/0.5 = Vi*t

Vi*t = 10.6  eq. 3

The vertical distance is

Vy = y1 + Vyi*t - 0.5gt²

also we know that

Vyi = Visin(60)

Vyi = Vi*0.866

It is given that V1 = 1.9 m and and Vy = 3 m is the vertical distance

3 = 1.9 + Vi*0.866*t - 0.5gt²

3 = 1.9 + Vi*0.866*t - 0.5(9.8)t²

3 = 1.9 + 0.866(Vi*t) - 0.5(9.8)t²

3 = 1.9 + 0.866(Vi*t) - 0.5(9.8)t²

1.1 = 0.866(Vi*t) - 4.9t²

0.866(Vi*t) = 4.9t² + 1.1

substitute Vi*t = 10.6 in above equation

0.866(10.6) = 4.9t² + 1.1

9.18 = 4.9t² + 1.1

4.9t² = 8.08

t² = 8.08/4.9

t² = 1.648

t = 1.28 sec

Finally, initial speed can be found by substituting the value of t into eq. 3

Vi*t = 10.6

Vi = 10.6/t

Vi = 10.6/1.28

Vi = 8.28 m/s

8 0
4 years ago
A uniform plank of mass 10kg and length 10m rests on two supports, A and B as shown. A boy of weight 500N stands at a distance o
kifflom [539]

Answer:

U² = 142.86 N

U¹ = 357.14 N

Explanation:

Taking summation of the moment about point A, we get the following equilibrium equation: (taking clockwise direction as positive)

W(2\ m) - U^2(7\ m) = 0

where,

W = weight of boy = 500 N

U² = reaction ay B = ?

Therefore,

(500\ N)(2\ m)-(U^2)(7\ m)=0\\U^2=\frac{1000\ Nm}{7\ m}\\

<u>U² = 142.86 N</u>

Now, taking summation of forces on the plank. Taking upward direction as positive, for equilibrium position:

W-U^1-U^2=0\\500\ N - 142.86\ N = U^1\\

<u>U¹ = 357.14 N</u>

3 0
3 years ago
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