A model rocket has a mass

of 0.2 kg, with a motor that
can provide a force of 100
N. A second model rocket is
being built with the same
motor, but it is being
designed to accelerate half
as much as the first rocket.
What kind of change can be
made in the design to
achieve this objective?
(1 point)
The mass of the
second rocket
should be 0.1 kg.
The mass of the
second rocket
should be 0.4 kg.
The mass of the
second rocket
should be 0.01 kg.
The mass of the
second rocket
should be 0.2 kg.

1 answer

To determine the mass of the second rocket needed to achieve half the acceleration of the first rocket, we can use Newton's second law, \( F = ma \), where \( F \) is the net force, \( m \) is the mass, and \( a \) is the acceleration.

First, we calculate the acceleration of the first rocket. Given:

  • Mass of the first rocket, \( m_1 = 0.2 \) kg
  • Force provided by the motor, \( F = 100 \) N

Using the equation, the acceleration \( a_1 \) of the first rocket is given by: \[ a_1 = \frac{F}{m_1} = \frac{100 \text{ N}}{0.2 \text{ kg}} = 500 \text{ m/s}^2 \]

The second rocket is designed to accelerate half as much: \[ a_2 = \frac{1}{2} a_1 = \frac{1}{2} \times 500 \text{ m/s}^2 = 250 \text{ m/s}^2 \]

Now, we use the same force (100 N) to find the mass of the second rocket, \( m_2 \), which will give us the desired acceleration: \[ F = m_2 \cdot a_2 \] \[ 100 \text{ N} = m_2 \cdot 250 \text{ m/s}^2 \] \[ m_2 = \frac{100 \text{ N}}{250 \text{ m/s}^2} = 0.4 \text{ kg} \]

Thus, to achieve half the acceleration, the mass of the second rocket should be 0.4 kg.

The correct answer is: The mass of the second rocket should be 0.4 kg.