Two examples of inventions that increase friction?

Physics

1 answer:

Ivan3 years ago

3 0

Answer:

My hard pp...............

Explanation:

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A rocket experiences a 45,000 N force as it accelerates at 30 m/s/s. What is the mass of the rocket?

Gre4nikov [31]

Answer:

15,00kg

Explanation:

here's your solution

=> force = 45,000N

=> acceleration = 30m/s^2

=> mass = ?

=> Mass = force/acceleration

=> mass = 45,000/30

=> mass = 15,00kg

hope it helps

6 0

3 years ago

A virtual image formed by a concave mirror is always enlarged. O True O False

Dmitry [639]

Answer:

True

Explanation:

A concave mirror produces real and inverted image when object placed at different locations beyond focus of the mirror.

A concave mirror produces virtual and erect and magnified image when an object placed between focus and the pole of the mirror.

8 0

3 years ago

A car is stopped at a traffic light. When the light turns green at t=0, a truck with a constant speed passes the car with a 20m/

s344n2d4d5 [400]

Answer:

At $t = (70 / 3) \; {\rm s}$ (approximately $23.3 \; {\rm s}$ .)

Explanation:

Note that the acceleration of the car between $t = 0\; {\rm s}$ and $t = 20\; {\rm s}$ ( $\Delta t = 20\; {\rm s}$ ) is constant. Initial velocity of the car was $v_{0} = 0\; {\rm m\cdot s^{-1}}$ , whereas $v_{1} = 35\; {\rm m\cdot s^{-1}}$ at $t = 20\; {\rm s}\!$ . Hence, at $t = 20\; {\rm s}\!\!$ , this car would have travelled a distance of:

$\begin{aligned}x &= \frac{(v_{1} - v_{0})\, \Delta t}{2} \\ &= \frac{(35\; {\rm m\cdot s^{-1}} - 0\; {\rm m\cdot s^{-1}}) \times (20\; {\rm s})}{2} \\ &= 350\; {\rm m}\end{aligned}$ .

At $t = 20\; {\rm s}$ , the truck would have travelled a distance of $x = v\, t = 20\; {\rm m\cdot s^{-1}} \times 20\; {\rm s} = 400\; {\rm m}$ .

In other words, at $t = 20\; {\rm s}$ , the truck was $400\; {\rm m} - 350\; {\rm m} = 50\; {\rm m}$ ahead of the car. The velocity of the car is greater than that of the truck by $35\; {\rm m\cdot s^{-1}} - 20\; {\rm m\cdot s^{-1}} = 15 \; {\rm m\cdot s^{-1}}$ . It would take another $(50\; {\rm m}) / (15\; {\rm m\cdot s^{-1}}) = (10/3)\; {\rm s}$ before the car catches up with the truck.