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3 years ago

3. A moving car covers a distance of 100 km in two hours. What is meant by this?

Physics

1 answer:

GenaCL600 [577]3 years ago

8 0

Answer:

50km /hour

Explanation:

The car moves 100km in two hours.

We can write a ratio like this:

100km : 2hr

Divide both sides by two and you get:

50km : 1hr

Meaning the moving car is moving 50km an hour.

Hope this helps :)

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1. A student adds water and sugar to a jar and seals the jar so that nothing can get in or out. The

Tcecarenko [31]

Answer:

The mass will stay the same throughout time

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3 years ago

A 12-kg projectile is launched with an initial vertical speed of 20 m/s. It rises to a maximum height of 18 m above the launch p

kirill115 [55]

Answer:

Change in mechanical energy, $\Delta E=283.2\ J$

Explanation:

It is given that,

Mass of the projectile, m = 12 kg

Speed of the projectile, v = 20 m/s

Maximum height, h = 18 m

Initially, the projectile have only kinetic energy. it is given by :

$K=\dfrac{1}{2}mv^2$

$K=\dfrac{1}{2}\times 12\ kg\times (20\ m/s)^2$

K = 2400 J

Finally, it have only potential energy. it is given by :

P = mgh

$P=12\ kg\times 9.8\ m/s^2\times 18\ m$

P =2116.8 J

The change in mechanical energy is given by :

$\Delta E=K-P$

$\Delta E=2400-2116.8$

$\Delta E=283.2\ J$

So, the change in mechanical energy is 283.2 J. Hence, this is the required solution.

8 0

3 years ago

6. An excited dog runs full-speed toward his owner who has just returned home from

mixas84 [53]

Answer:

v = 8.65 m/s

Explanation:

Given that,

Distance covered by the doge, d = 45 m

Time taken, t = 5.2 s

We need to find its average speed. The total distance covered divided by the total time taken is called the average speed of an object. So,

$v=\dfrac{45\ m}{5.2\ s}\\\\=8.65\ m/s$

So, the average speed is 8.65 m/s.

4 0

3 years ago

A hovering mosquito is hit by a raindrop that is 50 times as massive and falling at 8.4 m/s, a typical raindrop speed. How fast

kenny6666 [7]

The final velocity after the collision is 8.2 m/s

Explanation:

We can solve this problem by using the law of conservation of momentum: in fact, if we consider the system to be isolated (=no external unbalanced forces), the total momentum of the raindrop+mosquito must be conserved before and after the collision.

If the collision is perfectly inelastic, moreover, the raindrop and the mosquito stick together and travel at the same velocity v after the collision.

Mathematically:

$p_i = p_f\\m_1 u_1 + m_2 u_2 = (m_1+m_2)v$