Four movers pick up boxes. Each box has a different mass, and each mover applies a different amount of force to lift the box. Which box will have the greatest acceleration?(1 point)

Responses

a 20 kg box lifted with 40 N of force
a 20 kg box lifted with 40 N of force

a 10 kg box lifted with 60 N of force
a 10 kg box lifted with 60 N of force

a 20 kg box lifted with 60 N of force
a 20 kg box lifted with 60 N of force

a 10 kg box lifted with 40 N of force

5 answers

To determine which box will have the greatest acceleration, you can use Newton's second law of motion, which states that \( F = ma \) (force equals mass times acceleration). You can rearrange this formula to solve for acceleration:

\[ a = \frac{F}{m} \]

where \( F \) is the net force applied to the box and \( m \) is the mass of the box.

Let's calculate the acceleration for each box:

  1. 20 kg box lifted with 40 N of force \[ a = \frac{40 , \text{N}}{20 , \text{kg}} = 2 , \text{m/s}^2 \]

  2. 10 kg box lifted with 60 N of force \[ a = \frac{60 , \text{N}}{10 , \text{kg}} = 6 , \text{m/s}^2 \]

  3. 20 kg box lifted with 60 N of force \[ a = \frac{60 , \text{N}}{20 , \text{kg}} = 3 , \text{m/s}^2 \]

  4. 10 kg box lifted with 40 N of force \[ a = \frac{40 , \text{N}}{10 , \text{kg}} = 4 , \text{m/s}^2 \]

Now, we can compare the accelerations:

  • 20 kg box with 40 N: \( 2 , \text{m/s}^2 \)
  • 10 kg box with 60 N: \( 6 , \text{m/s}^2 \)
  • 20 kg box with 60 N: \( 3 , \text{m/s}^2 \)
  • 10 kg box with 40 N: \( 4 , \text{m/s}^2 \)

The box with the greatest acceleration is the 10 kg box lifted with 60 N of force, which has an acceleration of \( 6 , \text{m/s}^2 \).

A baseball has a mass of 145 g. A pitcher throws the baseball so that it accelerates at a rate of 80 m/s2. How much force did the pitcher apply to the baseball?(1 point)
Responses

1.8 N
1.8 N

11.6 N
11.6 N

65 N
65 N

0.6 N

To calculate the force applied to the baseball, you can use Newton's second law of motion, which states:

\[ F = m \cdot a \]

where:

  • \( F \) is the force,
  • \( m \) is the mass,
  • \( a \) is the acceleration.

First, convert the mass of the baseball from grams to kilograms, since the SI unit for mass is kilograms:

\[ 145 , \text{g} = 0.145 , \text{kg} \]

Now, substitute the values into the formula. Given the acceleration \( a = 80 , \text{m/s}^2 \):

\[ F = 0.145 , \text{kg} \cdot 80 , \text{m/s}^2 \]

Now calculate:

\[ F = 0.145 \cdot 80 = 11.6 , \text{N} \]

The force that the pitcher applied to the baseball is 11.6 N.

Which situation describes a negative acceleration?(1 point)
Responses

a swimmer moving at a constant velocity
a swimmer moving at a constant velocity

a runner slowing down at the end of a race
a runner slowing down at the end of a race

a diver jumping off a diving board and falling to the swimming pool below
a diver jumping off a diving board and falling to the swimming pool below

a bicycle increasing its velocity as the rider pedals harder

Negative acceleration, also known as deceleration, occurs when an object is slowing down or experiencing a reduction in its velocity over time.

Among the provided options, the situation that describes negative acceleration is:

a runner slowing down at the end of a race.

This is because the runner is decreasing their speed, which indicates negative acceleration. The other options describe constant velocity or increasing speed, which do not qualify as negative acceleration.