I'm giving out a lot of points for whoever me and answers correctly! 3 questions to answer! answer them ! : d
1 - which of these is a good example of newton's first law of inertia?
a) a ball sits motionless on the ground
b) a ball gathers speed as it rolls downhill
c) a ball accelerates as it falls out of a classroom window
d) a ball returns to your hand after you throw it up in the air
2 - the space shuttle is located exactly half way between the earth and the moon. which statement is true regarding the gravitational pull on the shuttle?
a) the moon pulls more on the shuttle
b) the earth pulls more on the shuttle
c) both are equal due to equal distances
d) both are equal due to the mass of the shuttle
3 - in which situation is the acceleration of the car negative?
a) the velocity of the car was 75/h over 4 hours
b) the velocity of the car reduced from 50 km/h to 35 km/h over one minute
c) the velocity of a car increased from 40 km/h to 75 km/h over 15 minutes
d) the velocity of a car was 45 km/h at 2: 00 pm and at 4: 00 pm the velocity of the car was 85 km/h

1. A) A ball sits motionless on the ground

Newton's First Law of inertia states that:

"When the forces acting on an object are balanced, the object stays at rest (if it was at rest) or continues its motion with constant velocity (if it was in motion)"

Among the options given, we see that the option

A) A ball sits motionless on the ground

is an example of this law: in fact, the ball sits at rest on the ground, the forces acting on it are balanced, so the ball stays at rest.

2. B) The earth pulls more on the shuttle

The gravitational attraction exerted by a planet on the shuttle is given by

where

G is the gravitational constant

M is the mass of the planet

m is the mass of the shuttle

r is the distance between the shuttle and the planet

In this problem, we are comparing the gravitational pulls exerted by the Earth and the Moon on the shuttle. The distance, r, is the same (because the shuttle is half-way), the mass of the shuttle m is the same, and G is the same. However, the mass of the Earth is greater than the mass of the Moon, so in the formula M is greater for the Earth: therefore, the Earth pulls more on the shuttle.

3. B) The velocity of the car reduced from 50 km/h to 35 km/h over one minute

The acceleration of the car is defined as the ratio between the change in velocity and the time taken:

where vf is the final velocity, vi is the initial velocity, and is the time taken.

In order to have a negative acceleration, the numerator must be negative: this means that the initial velocity, vi, must be greater than the final velocity, vf, and this situation occurs in option B), since the initial velocity is 50 km/h while the final velocity is 35 km/h.

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

15.3 cos 65 degrees trig