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3 years ago

20 pts.

2 answers:

6 0

The cup is acted upon by an unbalanced force which is the cars acceleration, but before it was an object at rest that stayed at rest. This jet propels their body forward.

KIM [24]3 years ago

3 0

Answer:

The cup is acted upon by an unbalanced force which is the acceleration of the car, but before it was an object at rest that stayed at rest.

Explanation:

Newton's first law of motion states, "if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force."

Since the cup is at rest while sitting on top of the car, it stays at rest as the car begins to move. Since the car is accelerating and the cup is not, the cup falls off of the car.

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A car starts from rest and speeds up to 30 m/s in a total of 6 s.

sveta [45]

5 m/s
30 divided by 6 is 5

4 0

2 years ago

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Find the volume of a sphere of radius 10 mm.

vredina [299]

Answer:

Explanation: This is done using the equation:

$\frac{4}{3} π R^{3}$

Because the Radius is a know value. We have the following.

$\frac{4}{3} π (10mm)^{3}$

Which is:

4188.7902 mm

5 0

3 years ago

A child's top is held in place upright on a frictionless surface. The axle has a radius of ????=3.21 mm . Two strings are wrappe

tekilochka [14]

Answer:

Angular momentum, $L=6.47\times 10^{-3}\ m$

Explanation:

It is given that,

Radius of the axle, $r=3.21\ mm=3.21\times 10^{-3}\ m$

Tension acting on the top, T = 3.15 N

Time taken by the string to unwind, t = 0.32 s

We know that the rate of change of angular momentum is equal to the torque acting on the torque. The relation is given by :

$\tau=\dfrac{dL}{dt}$

Torque acting on the top is given by :

$\tau=F\times r$

Here, F is the tension acting on it. Torque acting on the top is given by :

$\tau=2F\times r$

$2T\times r=\dfrac{L}{t}$

$L=2T\times r \times t$

$L=2\times 3.15\times 3.21\times 10^{-3}\times 0.32$

$L=6.47\times 10^{-3}\ m$

So, the angular momentum acquired by the top is $6.47\times 10^{-3}\ m$ . Hence, this is the required solution.

7 0

3 years ago

A shopping cart rolls from x=19.9m to x=5.40m with an average velocity of -0.418m/s. How much time did it take? (unit=s)

andrew11 [14]

Given

initial position = Xi= 19.9m

Final position Xf = 5.4m

Average velocity= Va = -0.418m/s

it shows displacement is reverse.

To find t=?

As Va = (Xf- Xi) / t

t = (Xf-Xi) / ( Va)

t = ( 5.4-19.9) / (-0.418)

t = (-14.5 ) / (-0.418) (-ve sign cancel out at numerator and denominator)

t =34.69 s

8 0

3 years ago

Compute the ratio of the rate of heat loss through a single-pane window with area 0.15 m2 to that for a double-pane window with

Rudik [331]

Answer:

2.80321285141

Explanation:

$L_g$ = Thickness of glass = 4.5 mm

$k_g$ = Thermal conductivity of glass = 0.8 W/mK

$R_0$ = Combined thermal resistance = $0.15\times m^2K/W$

$L_a$ = Thickness of air = 6.6 mm

$k_a$ = Thermal conductivity of air = 0.024 W/mK

The required ratio is the inverse of total thermal resistance

$\dfrac{2(L_g/k_g)+R_0+(L_a/k_a)}{(L_g/k_g)+R_0}\\ =\dfrac{2(4.5\times 10^{-3}/0.8)+0.15+(6.6\times 10^{-3}/0.024)}{(4.5\times 10^{-3}/0.8)+0.15}\\ =2.80321285141$

The ratio is 2.80321285141

4 0

3 years ago

Read 2 more answers