Physics Flashcards
We use models in physics because?
The real world is too complicated and we choose to ignore certain factors
How many significant figures are there in 7.3400?
5
Is the value of displacement always the same as the distance travelled?
No, the distance can be greater than the value of displacement
We assume that acceleration is constant. Why?
Because we would need to use calculus when the acceleration is not constant
Does negative acceleration mean deceleration?
No
In order to use equations (2.75), (2.76) and (2.77), we have to choose a coordinate system such that?
The y-axis points upwards
The graphical method of adding vectors is called?
The head-to-tail method
Can we subtract vectors graphically?
Yes, because subtracting a vector is the same as adding the opposite vector
When adding two vectors, the magnitude of the resultant vector?
Can be smaller than the sum of the magnitudes of the addends
The horizontal component of velocity of an object in a projectile motion
Is always constant but not zero
The vertical component of velocity of an object in projectile motion
Linearly depends on time
The vertical component of acceleration of an object in a projectile motion
Is always constant but not zero
The horizontal component of acceleration of an object in a projectile motion
Is always zero
In figure 3.47, Vboat is
The velocity of the boat relative to the water
In figure 3.48, Vw is
Velocity of the wind relative to the ground
Equation (3.91) is an application of equation (3.75) to the situation shown in figure 3.48. What’s wrong with equation (3.91)?
When the angle is defined as in figure 3.91, we can not apply equation (3.75)
The greater the net external force acting on an object,
A) The faster the object moves
B) The slower the object moves
Neither of the above is true
A free-body diagram is
A drawing of all external forces acting on a body
The net force acting on an object that is in a free-falling motion
Is equal to the gravitational force due to the earth
The tension in a cable is
A pulling force along the direction of the cable
The magnitude of the kinetic frictional force on an object
Is equal to the normal force multiplied by the coefficient of kinetic friction
The magnitude of the static force on an object
Can be less than the normal force multiplied by the coefficient of static friction
A drag force is
The resistant force when an object moves in a fluid
How does a drag force depend on velocity?
The greater the velocity, the greater the drag force
If you drop a stuffed animal from the CN tower, the toy will
Reach a constant velocity called terminal velocity
