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MAXImum [283]
2 years ago
8

A car advertisement states that a certain car can accelerate from rest to 70 km/h in 7 seconds. Calculate the acceleration of th

e car.
Physics
1 answer:
ankoles [38]2 years ago
3 0

Answer:

10 km/h

Explanation:

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What is the kinetic energy of an object with a mass of 50kg and is and it is traveling at a rate of 60m/s.
liq [111]

Answer:

90,000 J

Explanation:

Kinetic energy can be found using the following formula.

KE=\frac{1}{2}mv^2

where <em>m </em>is the mass in kilograms and <em>v</em> is the velocity in m/s.

We know the object has a mass of 50 kilograms. We also know it is a traveling at a rate of 60 m/s. Velocity is the speed of something, so the velocity of the object is 60 m/s.

<em>m</em>=50

<em>v</em>=60

Substitute these values into the formula.

KE=\frac{1}{2}*50*60^2

First, evaluate the exponent: 60^2. 60^2 is the same as multiplying 60, 2 times.

60^2=60*60=3,600

KE=\frac{1}{2}*50*3,600

Multiply 50 and 3,600

KE=\frac{1}{2}*180,000

Multiply 1/2 and 3,600, or divide 3,600 by 2.

KE=90,000

Add appropriate units. Kinetic energy uses Joules, or J.

KE=90,000 Joules

The kinetic energy of the object is 90,000 Joules

6 0
3 years ago
A stone that is dropped freely from rest traveled half the total height in the last second. with what velocity will it strike th
alexira [117]

Answer:

hellooooo :) ur ans is 33.5 m/s

At time t, the displacement is h/2:

Δy = v₀ t + ½ at²

h/2 = 0 + ½ gt²

h = gt²

At time t+1, the displacement is h.

Δy = v₀ t + ½ at²

h = 0 + ½ g (t + 1)²

h = ½ g (t + 1)²

Set equal and solve for t:

gt² = ½ g (t + 1)²

2t² = (t + 1)²

2t² = t² + 2t + 1

t² − 2t = 1

t² − 2t + 1 = 2

(t − 1)² = 2

t − 1 = ±√2

t = 1 ± √2

Since t > 0, t = 1 + √2.  So t+1 = 2 + √2.

At that time, the speed is:

v = at + v₀

v = g (2 + √2) + 0

v = g (2 + √2)

If g = 9.8 m/s², v = 33.5 m/s.

4 0
3 years ago
What type of subsurface material is able to store groundwater?
notka56 [123]
<span>Porous material has many spaces that can hold(store) groundwater.</span>
4 0
3 years ago
A box has a length of 18.1 cm and a width of 19.2cm tall ?
ladessa [460]
Volume = l*w*h = (18.1 cm)(19.2 cm)(20.3 cm) = 7,054 cm^3.
3 0
3 years ago
A bucket of mass m is hanging from the free end of a rope whose other end is wrapped around a drum (radius R, mass M) that can r
mr Goodwill [35]

Answer:

Explanation:

Let T be the tension .

Applying newton's second law on the downward movement of the bucket

mg - T = ma

On the drum , a torque of TR will be acting which will create an angular acceleration of α in it . If I be the moment of inertia of the drum

TR = Iα

TR = Ia/ R

T =  Ia/ R²

Replacing this value of T in the other equation

mg - T = ma

mg - Ia/ R²  = ma

mg =  Ia/ R² +ma

a ( I/ R² +m)= mg

a = mg / ( I/ R² +m)

mg - T = ma

mg - ma  = T

mg - m x mg / ( I/ R² +m) = T

mg - m²g / ( I/ R² +m ) = T

mg - mg / ( 1 + I / m R² ) = T

b ) T =  Ia/ R²

I = TR² / a

c ) Moment of inertia of hollow cylinder

I = 1/2  M ( R² - R² / 4 )

= 3/4 x 1/2 MR²

= 3/8 MR²

I / R² = 3/8 M

a = mg / ( I/ R² +m)

a = mg / ( 3/8 M + m )

T =  Ia/ R²

= 3/8 MR² x mg / ( 3/8 M + m ) x 1 /R²

= \frac{3mMg}{(3M +8m)}

7 0
3 years ago
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