Forces - 5 - Centripetal Force

University:
High School
Course:
High School Physics
Academic year:

2024
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469

Pages:

8
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Centripetal Force 1 2.7 Centripetal Force: ◼ ◼ ◼ Write this into your notebook Maintains a body in a circular motion Fc Directed towards the centre of rotation v Fc ◼ ◼ Velocity is always tangent to the circle of rotation Magnitude of velocity constant, but direction constantly changes Write this into your notebook ◼ ◼ If Fc disappears, rectilinear motion results Formula (magnitude): Mass (kg) Speed (m/s) Newtons (N) Radius of trajectory (m) ◼ ◼ ◼ Fc proportional to mass (kg) Fc proportional to speed2 (m/s) Fc inversely proportional to radius (m) Write this into your notebook Ex #1 A hammer thrower spins a hammer in a clockwise circle. Draw the circular path of the hammer and indicate direction of Fc and the instantaneous velocity. v Fc Ex #2 A machine spins a 35.0kg sphere in a horizontal circle attached to a cable. The radius of the circle is 1.15m. At what velocity does the sphere spin if there are 700.0N of tension in the cable? m = 35kg r = 1.15m Fc = 700N v=? v = 4.80m/s Ex #3 A constant centripetal force is exerted on a given mass over a constant radius, causing the mass to travel at a velocity. What force would have to be applied to triple the velocity? Force would have to be increased by 9 times Ex #4 A 125.0g ball is attached to a rotating ceiling fan by a string and rotates in a horizontal circle, as the string makes an angle of 20.0° below the horizontal. If the speed of the ball is 2.00m/s, what is the radius of the circle and what is the tension in the string? Fc=Tx 20.0° FT Fg=Ty Fg HW: pg 281 #1 & 2 pg 286 #9