Kinematics equation problem

  • Thread starter raincheck
  • Start date
  • Tags
In summary, to determine the required net force for an experimental rocket sled to accelerate from rest to 1600 km/hr in 1.8 seconds, we need to use the equation F=ma and solve for acceleration using kinematics. Once we have the acceleration, we can then multiply it by the mass of the sled (500 kg) to find the net force required. It's important to pay attention to units and use the correct ones (m/s^2 for acceleration).
  • #1
"An experimental rocket sled can be accelerated at a constant rate from rest to 1600 km/hr in 1.8 s. What is the magnitude of the required net force if the sled has a mass of 500 kg?"

I know I have to use
[sum of the] F = ma

and i was trying
= 500 x 1600,
but I'm sure there's something else I have to do to get the right answer, since this isn't working..
Physics news on
  • #2
Look again at the definition of acceleration. You have used velocity in place of acceleration. Be careful with your units. km/hr is not m/s.
  • #3
If you are having trouble, try solving it in terms of kinematics first. After you find the acceleration, then you can do what you did.

What is kinematics?

Kinematics is a branch of physics that studies the motion of objects without considering the forces that cause the motion.

What are the three kinematics equations?

The three kinematics equations are:

1. v = u + at

2. s = ut + 1/2at^2

3. v^2 = u^2 + 2as

How do I solve a kinematics problem?

To solve a kinematics problem, you need to identify the known and unknown variables, choose the appropriate kinematics equation, and substitute the known values into the equation. Then, solve for the unknown variable.

What units are used in kinematics equations?

The units used in kinematics equations are meters (m) for distance, meters per second (m/s) for velocity, and seconds (s) for time.

What is the difference between average and instantaneous velocity?

Average velocity is the total displacement divided by the total time taken, while instantaneous velocity is the velocity at a specific moment in time. Average velocity can be calculated for a whole journey, while instantaneous velocity can only be calculated at a specific point in time.