A student's life was saved in an automobile accident because an airbag expanded in front of his head. If the car had not been equipped with an airbag, the windshield would have stopped the motion of his head in a much shorter time. Compared to the windshield, the airbag:
Correct answer: D. Exerts a much smaller force
- A. Causes a much smaller change in momentum
- B. Exerts a much smaller impulse
- C. Causes a much smaller change in kinetic energy
- D. Exerts a much smaller force
Explanation
The correct answer is Option D: Exerts a much smaller force. When a collision occurs, the airbag extends the time it takes for the head to come to a stop, which decreases the average force experienced by the student. Although the momentum change (△p) and impulse remain the same with or without an airbag, the airbag reduces the force by increasing the time interval (△t) during which the momentum change occurs. Therefore, the force is smaller with an airbag. Option A is incorrect because the change in momentum remains consistent between scenarios. Option B is incorrect as the impulse does not change; it's the force applied over time that differs. Option C is incorrect because the change in kinetic energy depends on changes in velocity, which are the same in both cases.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Force and Motion
Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
Practise Force and Motion
1,416 free Force and Motion MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Force and Motion questions
A projectile is fired from ground with an initial velocity that has a vertical component of 20m/s and a horizontal component of 30m/s. Using g = 10m/s2, the distance from launching to landing points is:
Which of the curves on the graph below best represents the vertical component "vy" of the velocity versus the time t for a projectile fired at an angle of 45o above the horizontal?
A ball is thrown up with 20 ms-1 at an angle of 60° with x-axis. The horizontal velocity of the ball at the top position is:
Which of the following velocity-time graph represents infinite acceleration?
A train of length 150 in is going to north with a speed of 10ms-1. A parrot flies 5 ms-1 toward south parallel to the railway line. The time taken by parrot to cross the train is:
A body covers one half of its journey at 40ms-1 and the next half at 50ms-1. Its average velocity is: