Understanding Car Crashes: It's Basic Physics

(1:10) It is a fascinating place where research engineers assess the crash performance of vehicles by running tests and where they evaluate new _____________ to prevent injuries.

• vehicle colors
• crash dummies
• safety features
• fuel efficiency

(2:00) Why did the dummy get left behind? It’s called ________, the property of matter that causes it to resist any change in it motion.

• momentum
• velocity
• acceleration
• inertia

(2:15) Isaac Newton’s First Law of Motion states: A body at rest remains at _______ unless acted upon by an external force; and a body in motion continues to move at a constant speed in a straight line unless it is acted upon by an external ________.

• rest, force
• stillness, energy
• static, momentum
• motion, force

(3:20) Now watch what happens when the car crashes into a barrier. The front end of the car is crushing and absorbing _________which slows down the rest of the car.

• force
• energy
• momentum
• velocity

(4:00) In this case, it is the steering wheel and windshield that apply the ______ that overcomes the dummy's inertia.

• velocity
• acceleration
• momentum
• force

(4:20) Newton explained the relationship between crash forces and inertia in his __________________

• laws of gravity
• theory of relativity
• laws of motion
• principles of thermodynamics

(4:50) Fill in the blanks to complete the formula. Ft = ________, Ft = m∆v, m∆v = ________________

(a)  

(5:15) Momentum is inertia in motion. It's the product of an object's mass and its ___________.

• density
• force
• acceleration
• velocity

(5:50) Impulse is the product of ______ and the time interval during which the force acts.

• mass
• acceleration
• velocity
• force

(6:35) The wall applies a _______ force over a shorter time.

• negligible

• negative

• smaller

• larger