3.1.3 Introduction to Newton's Second Law Flashcards
Introduction to Newton’s Second Law
- Acceleration is proportional to force: a = F .
• Acceleration is inversely proportional to mass: a = 1/m
• Newton’s second law, F = ma, explains why objects accelerate.
• The mks unit of force is the Newton (N): . kg*m/s^2
In an experiment with a cart on an air track, a weight is attached to the cart by a string and a pulley. The motion of the cart in this situation is compared to its motion when the weight is doubled. These observations yield the equation a – F.
Which of the following best describes the motion of the cart and correctly states the equation?
The acceleration of the cart doubles when the weight is doubled. Acceleration is proportional to force.
The equation that state acceleration is proportion to force, a – F, and acceleration is inversely proportional to mass, a –1/m, fan be combined to form which of the following equations?
a = F/m
Consider a metal cart on an air track. A constant force is be applied to the cart by attaching a weight with a string and pulley assembly. Which of the following best describes the motion of the cart under a constant force?
The cart undergoes constant acceleration with a steadily increasing velocity.
Consider a metal cart on an airtrack. Ignoring friction, which of the following best explains when the cart would be at rest and when it would move on the airtrack?
The cart is at rest when left alone because, in the absence of a net force, it remains at rest. After being pushed, the cart maintains uniform motion because in the absence of a net force an object in uniform motion maintains its state of motion.
In an experiment with a cart on an air track, mass is added to the cart. The objective is to answer whether all objects accelerate the same when subject to the same force. The motion of the cart is compared with the cart’s motion when additional mass is placed on it. The observations result in the equation a – 1/m. Which of the following describes the motion of the cart and correctly states the equation?
The acceleration of the cart is half as fast when the mass on the cart is doubled. Acceleration is inversely proportional to mass.
Which of the following best defines the variables in newton’s second law, F = ma?
When an object is pushed or pulled, it is subject to a force; this is represented on the left side of the equation. The right side of the equation describes motion, in particular acceleration and kinematics (e.g., how velocity changes with time). The mass is the proportionality constant. Massive objects are sluggish and exhibit slower acceleration for given forces than less massive objects do. Overall, the right side describes motion and it indicates what happens when a force is applied to an object.
The equation a = F/m can be rewritten as F = ma, or force equals mass times acceleration. This is Newton’s second law. Which of the following best states how this equation explains why an object accelerates?
When a net force is applied to an object, the object will accelerate; objects accelerate when they are pushed or pulled
A scale designed to measure weight is a force meter capable of measuring other forces, and is calibrated, when __________.
two weights of equal mass move the scale’s needle twice as far as one of the weights
The Newton, N, is used to express force. It is derived from the equation F = ma, where m equals 1 kilogram and |a| equals 1 meter per second squared. A Newton, N, takes the place of F and is therefore expressed by the equation 1N = 1kg m/s^2. Given this information, which expression for force is correct for a cart with 4 Newtons of force applied to it?
F = 4 kg m / s^2
