Question

1.)Convert 72 miles per hour into meters per second

2.)Convert 50 lb into how many kg

3.) the gravitational force between two objects is 18N. If the distance between them is trippled and their masses are doubled, than what is the gravitational force of the two objects?

4.) A 1200 car accelerates it’s speed from 4 m/s to 10 m/s in 3 seconds. Find (1) the car average speed, (2) the car acceleration, (3) the distance traveled by , (4) the net force on the car.

Answer 1

Answer 2

1. To convert miles per hour (mph) to meters per second (m/s), we can use the following conversion factor: 1 mile = 1609.34 meters 1 hour = 3600 seconds

So, to convert 72 mph to m/s: 72 mph * (1609.34 meters / 1 mile) * (1 hour / 3600 seconds) ≈ 32.18 m/s

Therefore, 72 mph is approximately equal to 32.18 m/s.

2. To convert pounds (lb) to kilograms (kg), we can use the conversion factor: 1 pound = 0.45359237 kilograms

So, to convert 50 lb to kg: 50 lb * 0.45359237 kg ≈ 22.68 kg

Therefore, 50 lb is approximately equal to 22.68 kg.

3. The gravitational force between two objects is given by the formula: F = (G * m1 * m2) / r^2

Given: Initial gravitational force F = 18 N Distance tripled (r' = 3r) Masses doubled (m1' = 2m1, m2' = 2m2)

Using the formula, we can calculate the new gravitational force F': F' = (G * (2m1) * (2m2)) / (3r)^2

Since G, m1, m2, and r are constant, we can simplify the equation: F' = (4 * G * m1 * m2) / (9 * r^2)

Substituting the initial force F = 18 N: F' = (4 * 18 N) / 9 F' = 8 N

Therefore, the gravitational force between the two objects after tripling the distance and doubling the masses is 8 N.

4. Given: Initial velocity (u) = 4 m/s Final velocity (v) = 10 m/s Time (t) = 3 seconds

a) The average speed of the car can be calculated using the formula: Average Speed = Total Distance / Total Time

Since the car accelerates, the average speed will be the arithmetic mean of the initial and final velocities: Average Speed = (u + v) / 2 Average Speed = (4 m/s + 10 m/s) / 2 Average Speed = 7 m/s

Therefore, the average speed of the car is 7 m/s.

b) The car's acceleration can be calculated using the formula: Acceleration = (Change in Velocity) / Time

Change in Velocity = Final Velocity - Initial Velocity Change in Velocity = 10 m/s - 4 m/s = 6 m/s

Acceleration = (6 m/s) / (3 s) Acceleration = 2 m/s^2

Therefore, the car's acceleration is 2 m/s^2.

c) The distance traveled by the car can be calculated using the formula: Distance = (Initial Velocity + Final Velocity) / 2 * Time

Distance = (4 m/s + 10 m/s) / 2 * 3 s Distance = 14 m/s * 3 s Distance = 42 m

Therefore, the distance traveled by the car is 42 meters.

d) The net force on the car can be calculated using Newton's second law of motion: Net Force = Mass * Acceleration

Since the mass of the car is not given, we cannot determine the net force without that information.