PLEASE HELP 40 POINTS

Assuming no air resistance, all projectiles have:

Kitty [74]

Answer: Option C

C) accelerated vertical motion and constant horizontal motion.

Explanation:

If there is no air resistance then during the projectile movement the only force that causes an acceleration is the gravitational force.

We know that this force produces an acceleration of 9.8 m / s ^ 2 in the projectile.

As the gravitational force attracts the object towards the earth, then the acceleration that this force produces is always in the vertical direction. In the horizontal direction the object is not accelerated (because there is no air resistance).

Therefore the correct answer is option C.

"accelerated vertical motion and constant horizontal motion".

3 0

3 years ago

A car was going at 20m/s along a straight highway. The driver slams on the break to avoid hitting a deer. The car had a negative

My name is Ann [436]

I’m not to sure but I think the answer is -0.10

8 0

3 years ago

20. There are two electrical devices, one is electrical kettle of 2KW-200V and

RUDIKE [14]

Electrical kettle:

P = 2 KW = 2000 W

U = 200 V

⇒ I = P/U = 2000 / 200 = 10 A

We apply the Law of Ohm:

R = U / I = 200V / 10A = 20 Ω

=======

Electrical heater:

P = 1 KW = 1000 W

U = 240 V

⇒ I = P/U = 1000 / 240 = 4,16 A

We apply the Law of Ohm:

R = U / I = 240V / 4,16A = 57,69 Ω

Answer:

The device with the highest resistance is the electric heater.

.

6 0

4 years ago

Physical science!!!!!!helpppp

ipn [44]

Answer:

Option B

10.36 m/s

Explanation:

Using the first given equation, then velocity=distance/time

Since distance is provided as 200 m and time, t is 19.3 seconds then substituting these figures yields

v=200/19.3=10.3626943

Rounding off to 2 decimal places, then

v=10.36 m/s

6 0

3 years ago

100 g of Ice at -10°C is added into a

Andrei [34K]

Answer:

The mass of the juice responsible for melting the ice is 949.043 grams.

Explanation:

By the First Law of Thermodynamics, we understand that juice releases heat to the ice, which turns into water under the assumption that interactions between the ice-juice system and surroundings are negligible and energy processes are done in steady-state. Since juice is done with water, its specific heat will be taken as of the water. The process is described by the following formula:

$m_{i} \cdot [c_{i}\cdot (T_{1}-T_{2}) - L_{f} + c_{w}\cdot (T_{2}-T_{3})] + m_{w} \cdot c_{w}\cdot (T_{4}-T_{3}) = 0$ (1)

Where:

$m_{i}$ - Mass of ice, in grams.

$m_{w}$ - Mass of the juice, in grams.

$c_{i}$ - Specific heat of ice, in joules per gram-degree Celsius.

$c_{w}$ - Specific heat of water, in joules per gram-degree Celsius.

$L_{f}$ - Latent heat of fusion, in joules per gram.

$T_{1}$ - Initial temperature of ice, in degrees Celsius.

$T_{2}$ - Melting point of water, in degrees Celsius.

$T_{3}$ - Final temperature of the ice-juice system, in degrees Celsius.

$T_{4}$ - Initial temperature of the juice, in degrees Celsius.

If we know that $m_{i} = 100\,g$ , $c_{i} = 2.090\,\frac{J}{g\cdot ^{\circ}C}$ , $c_{w} = 4.18\,\frac{J}{g\cdot ^{\circ}C}$ , $L_{f} = 334\,\frac{J}{g}$ , $T_{1} = -10\,^{\circ}C$ , $T_{2} = 0\,^{\circ}C$ , $T_{3} = 10\,^{\circ}C$ and $T_{4} = 20\,^{\circ}C$ , then the mass of the juice is:

$m_{w} = \frac{m_{i}\cdot [c_{i}\cdot (T_{1}-T_{2}) - L_{f} + c_{w}\cdot (T_{2}-T_{3})]}{c_{w} \cdot (T_{3}-T_{4})}$

$m_{w} = \frac{(100\,g)\cdot \left[\left(2.090\,\frac{J}{g\cdot ^{\circ}C} \right)\cdot (-10\,^{\circ}C) - 334\,\frac{J}{g} +\left(4.18\,\frac{J}{g\cdot ^{\circ}C} \right)\cdot (-10\,^{\circ}C) \right]}{\left(4.180\,\frac{J}{g\cdot ^{\circ}C} \right)\cdot (-10\,^{\circ}C)}$

$m_{w} = 949.043\,g$

The mass of the juice responsible for melting the ice is 949.043 grams.

5 0

3 years ago