solve questions number 28
Answers
♊♊YOUR ANSWERS♍♍
✍(2) 14 m/s and 15 m/s
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EXPLANATION —
↪Actually welcome to the concept of NLM and Circular Motion
↪Basically we will balance the all forces
Balancing the forces we get
Mg - N = Mv²/R
For weightlessness N = 0
Therefore
Mv²/R = Mg
Here v is speed of car and R is radius of curvature
∴v = √(Rg)
Substituting the values R = 20 m and g =10 m/s²
⇒v = √(20 × 10)
⇒v = 14.14 m/s
Therefore the speed of car at the top of the hill is between 14 m/s to 15 m/s
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Answer:
14.14 m/s
OPTION B :- Between 14 m/s and 15m/s
Explanation:
★ KINEMATICS AND NLM ★
★ GIVEN ;
→ WEIGHTLESSNESS AT TOP OF HILL←
» RADIUS OF CURVATURE ( R ) = 20 m
★ The speed of ROLLER COASTER at top of hill ( V )= ???
♣ WE KNOW THAT ;
★ Before Reaching at top ;
» Forces are as follow ::: ---------------
» Fg ( Gravitational ) - Fn ( Normal ) = Fc ( Centripetal )
» mg - N = mV² / R ----- ( 1 )
★ NOW ; →→→
» WHEN ROLLER COASTER REACHES AT TOP OF HILL ; IT EXPERIENCES " WEIGHTLESSNESS "
So ;
★ CONTACT FORCE / NORMAL FORCE ( N ) ≈ 0
♣ EQUATION BECOMES .....
» Mg = MV² / R ---- ( 2 )
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→ Now ; Substituting values in EQUATION " 2 " ... we get ; →→
» Mg = MV² / R
» V² = g × R
» V² = 10 × 20
★» V = √ 200 = 14.14 m/s ★«
ANSWER :- HENCE ;
FOR RADIUS OF CURVATURE OF HILL OF 20m ; THE VELOCITY OF ROLLER COASTER AT TOP OF HILL IS ;
V = 14.14 m/s .
