Newton's first through third laws of motion
T or F It would take an unbalanced force to keep an object in motion @ constant velocity
False A unbalanced force is only required to accelerate
T or F If an object is at rest , then there's no force acting upon the object
False There's gravity & at least an upward force
T or F It would take an unbalanced force to keep an object in motion
False constant velocity = motion
Stoplight hangs @ rest ; Equilibrium? Net force?
Has equilibrium. No net force.
Two guys @ rest ; Equilibrium? Net force?
Has equilibrium. No net force.
A Mac truck & a buggie have a head-on collision. Action & reaction forces? Who has greater force? How? Who has greater acceleration? How?
Mac truck forces buggie right. Buggie forces Mac truck left. Both has equal force Buggie has greater acceleration b/c less mass.
Car accelerates to the right -> ; Equilibrium? Net force?
No equilibrium. Has net force.
Player slows down into the plate ; Equilibrium? Net force?
No equilibrium. Has net force.
FN = 3 N FF = 5 N FW = 3 N FA = 5 N
Object @ constant velocity (balanced force)
FN = 20 N FW = 20 N
Object @ rest / @ constant velocity
FN = 3 N FF = 5 N FW = 3 N
Object slowing down
FN = 40 N FW = 25 N
Object slowing down
T or F Newton's 1st Law of motion is applicable to both moving & non-moving objects
True Object @ rest stays @ rest / Object in motion stays in motion
T or F It would take an unbalanced force to cause an object to accelerate from rest
True w/out the unbalanced force the object would stay @ rest
The Top Thrill Dragster stratacoaster at Cedar Point Amusement Park in Ohio uses a hydraulic launching system to accelerate riders from 0 to 54 m/s in 3.8 seconds. What is the net force required to accelerate an 86 kg man?
a = v/t = 54.0 /8 = 6.75 m/s^2 Fnet = ma = (86 kg)(6.75 m/s^2) = 580.5 N
Billy wants to know his weight on the Moon. He knows that his weight on Earth is 652 N. Earth: g = 10 N/kg Moon: G = 1.8 N/kg
m = w/g = 652/10 = 65.2 kg w = mg = (65.2)(1.8) = 117.36 w= 117.36 N
What would a graph look like for the amount of friction occurring for different surface areas?
surface areas go up , friction goes up
A tennis player hits a tennis ball w/ a racuquet. If the net force on the ball is 1.95 N to the right & the acceleration of the ball is 30 m/s^2, what is the mass of the tennis ball?
1.95 N/ 30 m/s^2 = 0.065 m/s^2
In a physics lab, Kate & Rob use a hanging mass & pulley system to exert a 2.45 N rightward force on a 0.500 kg cart to accelerate it across a low friction track. If the total resistance force to the motion of the cart is 0.72 N, then what's the cart's acceleration?
2.45 N - 0.72 N = 1.73 N / 0.5 = 3.46 m/s^2
A rightward force of 302 N is applied to a 28.6 kg crate to accelerate it across the floor. Assuming the floor is frictionless, what is the acceleration of the crate?
302 N/28.6 kg = 10.6 m/s^2
Arnold(200 kg) & Susie(110 kg) are playing tug of war w/ a rope. Action & reaction forces? Who has greater force? How? Who has greater acceleration? How?
A: Rope forces Arnold right R: Arnold forces rope to the left A: rope forces Susie to the left R: Susie forces rope to the right Both has equal force Rope has greater acceleration b/c less mass.
Ben Tooclose is being chased through the woods by a bull moose that he was attempting to photograph. The enormous mass of the bull moose is extremely intimidating. Yet, if Ben makes a zigzag pattern through the woods, he will be able to use the large mass of the moose to his own advantage. Explain this in terms of inertia & Newton's 1st law of motion.
Ben forces moose to move back & forth b/c that will cause him to slow down more mass = more inertia = harder to move
A green car has a mass of 1500 kg. A red car has a mass of 2000 kg. Who has greater force? How? Who has greater acceleration? How?
Both are equal force b/c N3 Law Green car has greater acceleration b/c less mass.
