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ollegr [7]
3 years ago
10

The position-time equation for a certain train is xf=2.8m+(8.1m/s)t+(2.9m/s^2)t^2.

Physics
1 answer:
mash [69]3 years ago
3 0
The formula without numbers is
xf = xi + vxi(t) +  \frac{1}{2} (a) {t}^{2}
do the initial velocity would be
8.1 m/s
and the acceleration would be
2.9 m/s^2
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An object, when pushed with a net force F, has an acceleration of 4 m/s . Now twice the force is applied to an object that has f
hjlf

Answer:

B. 2 m/s

B. Acceleration = 4.05 m/s² and Tension = 297.5 N.

Explanation:

A force is applied on a mass m whose acceleration is 4 m/s

Force = mass × acceleration

a = F/m = 4 m/s

4 m/s = F/m

F = 4 m/s (m)

If  Force of 2F is applied on a mass of 4m ; it acceleration is as follows:

2F/4 m = F/ 2m

4m/s (m) / 2m = 2 m/s

a = 2 m/s

2.

Given that

mass m_1 = 30 kg

mass m_2 = 50 kg

\mu = 0.1

From the question; we can arrive at two cases;

That :

m_{2} a _ \ {net} }= m_2g - T   ----- equation (1)

m_{1} a _ \ {net} }=  T - mg sin \theta  - F ---- equation (2)

50 a = 50 g - T

30 a = T - 30 g sin 30 - 4 × 30 g cos 30

By summation

80 a =[ 50  - 30 * \frac{1}{2} - 0.1 *30* \frac{\sqrt{3}}{2}]g

80 a = 32. 4 × 10 m/s ²  (using g as 10m/s²)

80 a = 324 m/s ²

a = 324/80

a = 4.05 m/s²

From equation , replace a with 4.05

50 × 4.05 = 50 × 10 - T

T = 500 -202.5

T =297.5 N

8 0
3 years ago
Which situation is contrary to Newton’s first law of motion?
Bond [772]

Answer:

An object at rest stays at rest as long as unbalanced forces act on it.

Explanation:

Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.

In physics, Sir Isaac Newton's First Law of Motion is known as Law of Inertia and it states that, an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.

The inertia of a physical object such as a truck is greatly dependent or influenced by its mass; the higher the quantity of matter in a truck, the greater will be its tendency to continuously remain at rest.

Hence, the situation which is contrary to Newton’s first law of motion is that, an object at rest stays at rest as long as unbalanced forces act on it.

According to Newton’s first law of motion, an object at rest stays at rest as long as unbalanced forces do not act on it.

4 0
3 years ago
How many energy levels do the electrons occupy for a neutral Oxygen atom? *
Sophie [7]

Answer:

The neutral state of an atom is when it's net charge is zero; that is, the number of protons equals the numbers of electrons. Oxygen is the eighth element in the periodic table, with the symbol O. This means that it has eight electrons in its neutral state. Since it is neutral, it also has eight protons!

6 0
2 years ago
A 4.10 g bullet moving at 837 m/s strikes a 820 g wooden block at rest on a frictionless surface. The bullet emerges, traveling
atroni [7]

Answer:

(a) 1.85 m/s

(b) 4.1 m/s

Explanation:

Data

  • bullet mass, Mb = 4.10 g
  • initial bullet velocity, Vbi = 837 m/s
  • wooden block mass, Mw = 820 g
  • initial wooden block  velocity, Vwi = 0 m/s
  • final bullet velocity, Vbf = 467 m/s

(a) From the conservation of momentum:

Mb*Vbi + Mw*Vwi = Mb*Vbf + Mw*Vwf

Mb*(Vbi - Vbf)/Mw = Vwf

4.1*(837 - 467)/820 = Vwf

Vwf = 1.85 m/s

(b) The speed of the center of mass speed is calculated as follows:

V = Mb/(Mb + Mw) * Vbi

V = 4.1/(4.1 + 820) * 837

V = 4.1 m/s

6 0
3 years ago
The force between two point-charges of 0.040 C and 0.060 C separated by certain distance is 2.2 x 10^5 N. what is the distance b
Gala2k [10]

Answer:

im in hardvard dont cheat and get good grades and become a graduate

it is c

Explanation:

8 0
3 years ago
Read 2 more answers
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