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irina [24]
3 years ago
11

a car accelerates along a straight road from rest to 75km/h in 5.0s. What is the magnitude of its average acceleration? show up

solutions​
Physics
1 answer:
kykrilka [37]3 years ago
5 0

Answer:

4.186 m/s^2

Explanation:

First, convert km/hr to m/s:

(75 km/hr)(1000m/1km)(1hr/60min)(1min/60s) = 20.83 m/s

Then, divide 20.93 m/s by 5.0s

(20.93 m/s) / (5.0s) = 4.186 m/s^2

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Under ideal conditions (no atmospheric interference of any kind), if I hit a golf ball at an angle of 25 degrees at an initial s
g100num [7]

Answer:

The required angle is (90-25)° = 65°

Explanation:

The given motion is an example of projectile motion.

Let 'v' be the initial velocity and '∅' be the angle of projection.

Let 't' be the time taken for complete motion.

Let 'g' be the acceleration due to gravity

Taking components of velocity in horizontal(x) and vertical(y) direction.

v_{x} =  v cos(∅)

v_{y} =  v sin(∅)

We know that for a projectile motion,

t =\frac{2vsin(∅)}{g}

Since there is no force acting on the golf ball in horizonal direction.

Total distance(d) covered in horizontal direction is -

d = v_{x}×t = vcos(∅)×\frac{2vsin(∅)}{g} = \frac{v^{2}sin(2∅) }{g}.

If the golf ball has to travel the same distance 'd' for same initital velocity v = 23m/s , then the above equation should have 2 solutions of initial angle 'α' and 'β' such that -

α +β = 90° as-

d = \frac{v^{2}sin(2α) }{g} = \frac{v^{2}sin(2[90-β]) }{g} =\frac{v^{2}sin(180-2β) }{g} = \frac{v^{2}sin(2β) }{g} .

∴ For the initial angles 'α' or 'β' , total horizontal distance 'd' travelled remains the same.

∴ If α = 25° , then

     β = 90-25 = 65°

∴ The required angle is 65°.

5 0
3 years ago
Read 2 more answers
A spring 1.50 m long with force constant 448 N/m is hung from the ceiling of an elevator, and a block of mass 10.9 kg is attache
GuDViN [60]

Answer:

Explanation:

Let the extension in the spring be x .

restoring force = weight of block

kx = mg

x = \frac{10.9\times9.8}{448}

= 23.84 cm

b )

When the elevator is going upwards

Restoring force = mg + ma

k x₁ = 10.9 ( 9.8 + 1.89 )

x₁ = 28.44 cm

( y coordinate will  be - ( 28.44 - 23.84 ) = - 4.6 cm )

c ) When the cable snaps , both elevator and block undergo free fall . In this case apparent g = 0

Since the spring is stretched by 28.44 cm , a restoring force continues to act on the block which is equal to

.2844 x 448

= 127.41 N

So a net acceleration a will act on the block

a = 127.41 / 10.9

= 11.68 m / s²

The block will undergo SHM with amplitude equal to 28.44 cm .

3 0
3 years ago
The position vector of a particle of mass 1.70 kg as a function of time is given by r with arrow = (6.00 î + 5.70 t ĵ), where r
ollegr [7]

Answer:

The angular momentum of the particle is 58.14 kg m²/s along positive z- axis and is independent of time .

Explanation:

Given that,

Mass = 1.70 kg

Position vector r=(6.00\hat{i}+5.70 t \hat{j})

We need to calculate the angular velocity

The velocity is the rate of change of the position of the particle.

v = \dfrac{dr}{dt}

v=\dfrac{d}{dt}(6.00\hat{i}+5.70 t \hat{j})

v=5.70\hat{j}

We need to calculate the angular momentum of the particle

Using formula of angular momentum

L=r\cdot p

Where, p = mv

Put the value of p into the formula

L=m(r\times v)

Substitute the value into the formula

L=1.70(6.00\hat{i}+5.70 t \hat{j}\times5.70\hat{j})

L=1.70\times34.2

L=58.14\ kgm^2/s

Hence, The angular momentum of the particle is 58.14 kg m²/s along positive z- axis and is independent of time .

7 0
3 years ago
How are theories supported in the scientific community?
mafiozo [28]
They are unproven but accepted as fact.
Many experiments support them but they can be disproven by the results of a single experiment. Until then, they stand.
The third statement is correct.
7 0
3 years ago
According to the graph, during which time interval are the particles in the air slowing down?
kenny6666 [7]
Answer b like the last time should be it
4 0
2 years ago
Read 2 more answers
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