3. List (by number and name) and define with words or equations each of Newton's Laws governing linear motion. Give a real life example illustrating each.
4. A person performs a standard long jump from the ground (takeoff and landing surfaces the same). Using a total flight time of 0.43 s and a horizontal
displacement of 2.5 m, calculate the following.
a. Vertical velocity at takeoff.
b. Horizontal velocity at takeoff.
c. Actual (resultant) velocity at takeoff.
d. Angle of takeoff.
e. Peak height.
6. Identify five examples of torque in human activity, and identify the force and moment arm associated with the torque.© BrainMass Inc. brainmass.com December 24, 2021, 7:52 pm ad1c9bdddf
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3. Newton's first law of motion: According to this law "a body continues to be in state of rest or uniform motion along a straight line, unless it is acted upon by some external force to change the state."
Example- a bike can not change its straight line path on its own. We have to apply force on its handle.
Newton's second law of motion: According to this law "the rate of change of linear momentum of a body is directly proportional to the external force applied on the body and this change is in the direction of application of the force" i.e.
Example- rocket propulsion is based on this law.
Newton's third law of motion: According to this law "to every action there is always a equal and opposite reaction" i.e.
Example- when a gun is fired the bullet moves forward (action) and the gun recoils backward (reaction)
4. In projectile motion
Where is the angle of projection with horizontal.
(a)In vertical direction
(c) = =
6. Example of torque
(a) To open or close the door we apply torque on knob. Moment arm in this case is distance of the knob at one end to other end. Force is mechanical.
(b) To unscrew a nut torque is applied. Length of wrench is moment arm. Force is mechanical.
(c) sea- saw is example of application of torque. Moment arm is half the length of sea-saw. Force is applied at the ends in opposite directions.
(d) In rotating a wheel we apply tangential force and the radius of the wheel is the moment arm.
(e) To swing a ball the cricketer apply tangential force on the ball. The radius of the ball is moment arm in this case.