Question

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

3 answers

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

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

Where:

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

Let’s calculate the acceleration for each option:

  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, let's summarize the calculated accelerations:

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

The box with the greatest acceleration is the 10 kg box lifted with 60 N of force, with 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

11.6 N
11.6 N

65 N
65 N

0.6 N
0.6 N

1.8 N
1.8 N

To find the force applied by the pitcher to the baseball, we can use Newton's second law of motion, which is given by the formula:

\[ F = ma \]

Where:

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

First, we need to ensure that the mass is in kilograms (kg) since the standard unit of mass in physics is kilogram. The baseball's mass is given as 145 grams, which we can convert to kilograms:

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

Next, we have the acceleration provided:

\[ a = 80 , \text{m/s}^2 \]

Now, we can substitute the mass and acceleration into the formula to find the force:

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

Calculating this gives:

\[ F = 11.6 , \text{N} \]

Thus, the force applied by the pitcher to the baseball is 11.6 N.