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4 years ago

A car accelerates from rest for 8.0 s, and reaches a speed of 66 m/s. How far will the

Physics

1 answer:

PSYCHO15rus [73]4 years ago

3 0

Answer: C

Explanation:

Find the acceleration using this kinematic equation:

$v_f=v_i+at\\66=0+a*8\\a=8.25m/s^2$

Now use this kinematic equation to find the displacement:

$v_f^2=v_i^2+2a*d\\66^2=0^2+2(8.25)d\\4356=16.5d\\d=264m$

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A 0.500-kg potato is fired at an angle of 80.0° above the horizontal from a PVC pipe used as a "potato gun" and reaches a height

lions [1.4K]

Answer:

(a) $47.15ms^{-1}$

(b) $2470.13ms^{-2}$

Explanation:

From Newton's second law of motion

F=ma where m is mass, a is acceleration and F is net force

Also from kinetic equation of motion, velocity and displacement are related using equation

$v^{2}=u^{2}+2sa$

Where v is final velocity, u is initial velocity, a is acceleration and s is displacement

From the free body diagram attached, final velocity at maximum height is 0 and initial velocity is $usin80^{o}$

Also, the vertical component can be written as

$v_{y}^{2} }=u_{y}^{2} } -2gs$ The negative sign before 2gs means displacement is opposite the gravitational force

Where g is acceleration due to gravity, $u_{y}$ is vertical component of initial velocity and $v_{y}$ is vertical component of final velocity

Since $v_{y}$ is 0

$u_{y}^{2} } =2gs$

s=110 and g is taken as 9.8

$u_{y}=\sqrt{2*9.8*110}=46.43275$

$u_{y}=46.43ms^{-1}$

Also, it's evident that the vertical component of initial velocity is $u_{y}=u_{i}sin \theta$ where $\theta$ is angle of projection and $u_{i}$ is resultant velocity

Making $u_{i}$ the subject we obtain $u_{i}=\frac {u_{y}}{sin \theta}$

Since $u_{y}$ and $\theta$ are known as $46.43ms^{-1}$ and $80^{o}$ respectively, then $u_{i}=\frac {46.43ms^{-1}}{sin 80^{o}}=47.15ms^{-1}$

Therefore, the velocity of potato is $47.15ms^{-1}$

(b)

Displacement depends on length of tube hence s=0.450m hence going back to kinetic equation $v^{2}=u^{2}+2sa$

The final velocity v is answer in part a which is $47.15ms^{-1}$ , initial velocity u is $0ms^{-1}$ hence the equation is re-written as

$v^{2}=2sa$ and making a the subject we obtain

$a=\frac {v^{2}}{2s}$

$a=\frac {47.15^{2}}{2*0.450}=2470.13ms^{-2}$

Therefore, average acceleration is $2470.13ms^{-2}$

(c)

From Newton's second law of motion, F=ma where m=0.500kg and a is $2470.13ms^{-2}$

Therefore, the average force of potato is

F=0.5*2470.13=1235.06N

F=1235.06N

The weight, W of potato is given by W=mg

Taking R as ratio of average force and weight of potato

$R=\frac {F}{W}=\frac {F}{mg}$ and since F=1235.06, m=0.500kg and g=9.8

$R=\frac {1235.06}{0.500*9.8}$ =252.05

Therefore, ratio of average force to weight is 252.05

8 0

4 years ago

The approximate mass of a nickel in kilograms is

mart [117]

The nickel has a mass of approximately 0.005kg

5 0

3 years ago

#1 “A persons body continuing to move forward even though the car comes to a sudden stop” Which newtons Law Do they pertain? A:

Aloiza [94]

#1 “A persons body continuing to move forward even though the car comes to a sudden stop” Which newtons Law Do they pertain?
A: First Law 

#2 “A fighter Pilot Feels Massive Amounts of forcé when his plane turns sharply” Which Newton Law?
A: First Law.
You were following the Newton's first law and kept your velocity straight until you departed from linear motion when you turn sharply; you are forced to follow the curve. The force that the jet exerts on you is called centripetal force and is suitable for the center of curvature of the forced traveling path.

#3 “ A Paddle wheel boat pushed on water and the water pushes back causing the boat to move” Which Netwons Law?
C: Third Law

3 0

3 years ago

What is a vector?

ad-work [718]

A quantity that has magnitude and direction

7 0

4 years ago

If released, the chemical potential energy will cause the coal atoms and molecules to vibrate violently, and this internal kinet

nata0808 [166]

Answer:

A. burn the coal

Explanation:

Burning the coal is only the way to convert the stored chemical energy of the coal into the the kinetic energy of its molecules that can then be transferred to the nearby objects in the form of heat by the various modes of heat transfer such as conduction, convection or radiation.

Conduction is the contact method of heat transfer in which the adjacent atom transfers the vibration kinetic energy.

Convection is the bulk mode of heat transfer in which the bulk mass of molecules moves near and far to the heat source.

Radiation is the distant mode of heat transfer in the form of electromagnetic waves.

5 0

3 years ago

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