PHYSICS
HIGH SCHOOL

Answer:

- Because work=forcexdisplacementxcos(angle)
- so if there is an angle between thedirection of force and the displacement the work done will be less but if there is no angle the work will be greater

MIDDLE SCHOOL

a table tennis ball with a mass of 0.003 kg and a soccer ball with a mass of 0.43 kg are both set in motion at 16 m / s calculate and compare the momentum of both balls

Answer:

Momentum of Soccer ball is more than the momentum of tennis ball

Explanation:

As we know that momentum is defined as the product of mass and velocity

so we have

momentum of the tennis ball is given as

Momentum of soccer ball is given as

Momentum of Soccer ball is more than the momentum of tennis ball

Using the momentum formula: p=mv

.003*16=.048

.43*16=6.88

.003*16=.048

.43*16=6.88

COLLEGE

In order to rendezvous with an asteroid passing close to the earth, a spacecraft must be moving at 8.50×103m/s relative to the earth at a distance 2.50×108m from the center of the earth. At what speed must this spacecraft be launched from the earth's surface? Neglect air resistance and the gravitational pull of the moon.

Answer:

v₀ = 13.9 10³ m / s

Explanation:

Let's analyze this exercise we can use the basic kinematics relationships to love the initial velocity and the acceleration we can look for from Newton's second law where force is gravitational attraction.

F = m a

G m M / x² = m dv / dt = m dv/dx dx/dt

G M / x² = dv/dx v

GM dx / x² = v dv

We integrate

v² / 2 = GM (-1 / x)

We evaluate between the lower limits where x = Re = 6.37 10⁶m and the velocity v = vo and the upper limit x = 2.50 10⁸m with a velocity of v = 8.50 10³ m/s

½ ((8.5 10³)² - v₀²) = GM (-1 /(2.50 10⁸) + 1 / (6.37 10⁶))

72.25 10⁶ - v₀² = 2 G M (+0.4 10⁻⁸ - 1.57 10⁻⁷)

72.25 10⁶ - v₀² = 2 6.63 10⁻¹¹ 5.98 10²⁴ (-15.3 10⁻⁸)

72.25 10⁶ - v₀² = -1.213 10⁸

v₀² = 72.25 10⁶ + 1,213 10⁸

v₀² = 193.6 10⁶

v₀ = 13.9 10³ m / s

MIDDLE SCHOOL

Is P4O8 a ionic or covalent compound??

Salt is made up of sodium and chloride and is ionically bonded. Sugar, on the other hand, is composed of carbon, oxygen, and hydrogen and has covalent bonds. A salt molecule is made up of one sodium atom and one chlorine atom. For salt to be made, the sodium atom must lose an electron and become a sodium ion.

MIDDLE SCHOOL

A student measured the density of gold to be 19.1 g/cm^3. The accepted value of the density of gold is 19.3 g/cm^3. What is the percent error of the student's measurement? A. 0.20%

B. 1.71%

C. 1.04%

D. 1.39%

Answer:

C. 1.04%

Explanation:

The following information has been provided;

Actual density of gold; 19.3 g/cm^3

Observed/measured density of gold; 19.1 g/cm^3

The formula for percent error is given as;

((actual value - observed value)/actual value)) * 100

The percent error of the student's measurement is thus 1.04%