Physics unit test 1:
When you stand @ rest on a pair of bathroom scales, the readings on the scales will ALWAYS:
+ to = your weight.
What is the acceleratuon of a car that maintains a consatnt veloicty of 100 km/h for 10 s?
0 m/s^2.
A cart is pushed & undergoes a certain acceleration. If the force is held constant & the mass of the cart doubles, its acceleration would be:
1/2.
A 1-kg mass @ the Earth's surface weights about:
10 N.
The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is:
10 N.
Use Newton's 2nd law to answer this ?: the acceleration of a vertically thrown ball @ the top of its path is:
10 m/s^2 (@ the top, gravity still acts, so there's a force on it. It still has mass. So in accord w a = F/m, a cannot be 0).
Refer to Figure 2-6. If you start from the Bakery, travel to the Cafe, & then to the Art Gallery, what is the distance you have traveled?
10.5 km
A force interaction REQUIRES @ least:
2 forces.
Refer to figure 2-6. If you start from the bakery, tarvel to the Cafe, & then to the Art Gallery, what is your displacement?
2.5 km south.
The force of gravity acting on a 2kg melon is:
20 N.
The average speed of a horse that gallops a distance of 10 km in a time of 30 min is:
20 km/h.
When you walk @ an average speed of 4 m/s, in 5 s you'll cover a distance of:
20 m.
A car starts from rest & accelerates @ 6.00 m/s^2. How far does it travel in 3.00 s?
27.0 m
An astronaut stands by the rim of a crater on the moon, where the acceleration of gravity is 1.62 m/s^2. To determine the depth of the crater, she drops a rock & measures the time it takes for it to hit the bottom. If the time is 6.3 s, what is the depth of the crater?
32 m.
The average speed of a deer traveling a distance of 2 km in a time of 1/2 hour is:
4 km/h.
If a ball rolls down an inclined plane & picks up 4 m/s each second it rolls, its acceleration is:
4 m/s^2.
An axe is swung against a tree w a blow of 4000N. The force that acts on the axe during this event is:
4000 N
You run horizontally @ 4 m/s in a vertically falling rain that falls @ 4 m/s. Relative to you, the raindrops are falling @ an angle of:
45 degree.
An object is pulled northward w a force of 10 N & southward w a force of 15 N. The magnitude of the net force on the object is
5 N.
Nellie runs the length of a 100-yard football field in a time of 20 secs. Her average running speed is:
5 yeards/s.
The resultant of a 30-N force & a 40-N force cannot possibly be:
80 N.
Refer to figure 2-6. If you start from the bakery, travel to the art gallery, & then to the cafe, in 1.0 hour, what is your average speed:
9.0 km/hr.
Horizontal & vertical components of velocity are = when the projection angle is:
= to 45 degree
Two identical carts have a compressed spring btw them. When the spring is released, the carts recoil from each other w oppositely directed accelerations that are:
=.
Which has 0 acceleration? An object:
@ rest, moving @ constant veloicty, & in mechanical equilibrium.
An object in mechanical equilibrium is an obejct:
@ rest, moving w constant velocity, & having no acceleration.
According to Newton's law of inertia, a rail road train in motion should continue going forever even if its engine is turned off. We never observe this bc railroad trains
ALWAYS have forces that OPPOSE their motion.
The change in velocity over a specific amount of time:
Aceleration
Total distance traveled during a specific time:
Average speed
Galileo used inclined planes ti speed up acceleration so he could measure it more quickly.
False
When the velocity & acceleration of an object have OPPOSITE signs, the speed of the object increases.
False
Equilibrium ONLY occurs when objects are @ rest.
False.
Any PUSH or PULL.
Force
The scientist to 1st introduce the concept of inertia was:
Galielo
When an object is in free fall, the force(s) acting on it is/are?
Gravity ONLY.
The property of matter that RESIST changes in is motion.
Inertia.
How fast an object is going @ a particular INSTANT in time:
Instantaneous speed.
An object will move toward its NATURAL place & stop:
Natural motion.
The total of all forces =ed together
Net force
Defined as a "quantity w magnitude ONLY":
Scalar
Suppose that an object travels from 1 point in space to another. Make a comparison btw the displacement & the distance tarveled.
The displacement is eitehr less than or = to the distance traveled.
A lead-filled tennis ball & a regular tennis ball are dropped from the top of a tall building @ the same time. Air drag does affect motion. Which reacjes the ground 1st?
The lead-filled 1 (the heavier 1 has a greater terminal speed & hits the ground 1st).
A vector is a quantity that needs both magnitude & direction for a complete description.
True
Acceleration measures how quickly your velocity is changing.
True
All motions are relative.
True
Free fall is the motion of an object subject ONLY to the influence of gravity.
True
It is possible to have a 0 acceleration, & still be moving.
True
When the veloicty & acceleration of an object have the SAME sign, the speed of the object increases.
True.
Defined as a "quantity w magnitude & direction":
Vector
A motorcycle undergoes acceleration when:
a non net force acts on it.
The force of air friction (air drag) against a falling sack of potatoes:
acts upward, increases w increased area, & increases w increased speed.
You're lying on the sand on a breezy day when a peskly fly wishes to join you. The breeze is blowing @ a steady 2 m/s. In order for the fly to land on you, it should hover overyou while flying:
against the breeze @ 2 m/s.
When your mass increases, your weight:
also increases.
Your average speed in skateboarding to your freind's house is 5 mi/h. It is possible that your instantaenous speed @ some point was:
any of these: less than 5 mi/h, 5 mi/h, & more than 5 mi/h.
The amount of air resistance that acts on a wingsuit flyer (& a flying squirrel) depends on the flyer's:
area & speed
If noe xternal forces are acting on a moving obejct, it will:
continue moving @ the same velocity.
As mass is +ed to a pushed object, its acceleration:
decreases (more mass means less acceleration).
The 2 measuremenrs necessary for calcualting average speed are:
distance & time.
Sophia runs along the aisle of a train car that moved @ 8 m/s. Sophia's speed relative to the floor is 3 m/s. Her speed relative to an observer @ rest on the ground is:
either 11 m/s or 5 m/s depending on whether she runs in the same or opposite direction to the train's motion.
When the neck of an air-filled balloon is united & air escapes, the balloon shoots through the air. The force that propels the balloon is provided by the ____.
ejected air.
When a squid pushes against the water, the squid moved forward bc the water:
exerts a net forward force.
Whereas Aristotle relied on logic in explaning nature, Galileo relied on:
experiment.
Whirl a rock @ the end of a string & it follows a circualr path. If the string breaks, the tendency of the rock is to:
follow a straight-line path.
If action is a foot kicking a soccer ball, the reaction is an force on the:
foot.
A motor scooter undergoes acceleration when it:
gains speed, decreases speed, & changes direction.
An object w a mass of 1 kg on Earth:
has the same mass on the Moon & weighs less on the Moon.
During each 2nd of free fall, the speed of an obejct:
increased by the same amount.
Mass is most closely related to:
inertia
1 object that has the twice as much mass as another object also have twice as much:
inertia.
If your automobible runs out of fuel while you are drivin the engine stops you, but you do not come to an abrupt stop. The concept that most explains why is:
inertia.
A glance @ your speedometer will tell you your:
instantaneous speed.
For a given force, acceleration & mass are:
inversely proportional to each other.
Whenever the net force on an object is 0, the acceleration:
is 0.
Whenever 1 obejct exerts a force on a 2nd object, the 2nd object exerts a force on the 1st that:
is OPPOSITE in direction, is = in magnitute, & occurs @ the same time.
When a ball increases in speed by the same amount each second, its acceleration:
is constant.
The net force on a kicked soccer ball can be 0 when:
it is kicked by 2 feet w = & opposite amounts of force.
When we say that 1 kg weighs 10 N, we mean that:
it's true @ Earth's surface.
A stone is thrown staright up. When it reaches its highest point,
its velocity is 0 & its acceleration is NOT 0.
The amount of force w which a boxer's punch lands depends on the
mass of what's being hit
A kilogra is a measure of an object's:
mass.
When a net force acts on an object, its acceleration depends on the obejct's:
mass.
When you jump vertically upward, strickly speaking, you cause Earth to:
move downward.
When a rocket ship accelerating in outer space runs out of fuel it:
no longer accelerates.
When Nellie Newton hangs by a pair of ropes @ diff angles to the vertical, the rope tension is greater in the rope that makes the:
smallest angle to the vertical,
A boulder falls due to gravity. The reaction to the force on the boulder is:
the boulder pulling on Earth.
The reason a 10kg rock falls no faster than a 5kg rock in free fall is that:
the force/mass ratio is the same for both
Your weight is:
the gravitational attraction btw you & earth.
The force that propels a heavy truck along a highway is provided by:
the highway pushing back on the wheels of the truck.
A cart is pushed & undergoes a certain acceleration.If it were pushed w twice the force while its mass doubles, its acceleration would be:
the same (the ratios F/m & 2F/2m are the same. So acceleration is the same either way).
If you push a crate across a level floor @ constant speed, the friction btw the carte & floor is:
the same amount as your pushing force.
A mosquito has a collision w the windshielf of a massive high-speed truck. The force of impact on the mosquito is ____ the force on the truck, & the acceleration of the mosquito is ____ the deceleration of the truck.
the same as; more than
Earth pulls on the Moon w a certain force. Relative to this force, the oull of the moon on earth is:
the same.
A force is a push or pull that is REQUIRE to chaneg the:
the state of motion of an object
A massive truck & a golf cart have a head-on collision w = amounts of force. The least amount of acceleration occurs for
the truck
Suppose you hike a distance of 1 km in a time of 1/2 hour. Then your average speed isL
twice 1 km/h.
As an object freefly falls, its:
velocity increases.
The force of friction btw 2 surfaces can act:
whether or not the surfaces move relative to each other.