On a banked curve, the force(s) that provide(s) the centripetal force for a turning car is (are)

Question

BlackTom AI · Accepted Answer

The centripetal force is the net horizontal (radial) force pointing toward the center of the curve. On a banked road the contact forces from the road (normal and friction) have components that can produce that horizontal net force.

Relevant concepts and forces:
- Normal force N: acts perpendicular to the road surface; because the surface is tilted by angle θ it has a horizontal inward component N sinθ and a vertical component N cosθ.
- Friction f (static): acts along the surface and can have a horizontal component f cosθ and a vertical component f sinθ (sign depends on whether it points up or down the slope).
- Weight mg: acts vertically downward and has no horizontal component, so it cannot directly provide centripetal (radial) force.

Step-by-step reasoning (with equations):
1. Choose axes: x horizontal toward curve center, y vertical upward.
2. Sum of forces in x (radial) gives the centripetal requirement:
   N sinθ + f cosθ = m v^2 / r
   (both N and f can contribute to the inward force).
3. Sum of forces in y (vertical equilibrium, if no vertical acceleration):
   N cosθ − f sinθ = mg
4. These two equations show explicitly that the horizontal (centripetal) force is provided by components of N and of f. In the special frictionless design-speed case f = 0, N alone supplies the needed horizontal component (N sinθ = m v^2/r). In general, however, both N and friction contribute.

Why other choices are incorrect:
- (a) Friction alone is incomplete because the normal’s horizontal component is generally present and contributes.
- (c) Gravity (mg) is vertical only and cannot produce the necessary horizontal centripetal force.
- (d) “None of the above” is wrong because contact forces do provide the centripetal force.

Conclusion: therefore the correct answer is b. The friction between the car and the road and the normal force of the road on the car together provide the centripetal force (option b).

On a banked curve, the force(s) that provide(s) the centripetal force for a turning car is (are)单项选择题

类似问题

A 905 kg car is driving in a roundabout on a frictionless banked track as shown in the diagram below.The angle of banking, [math: θ=15.4∘].What is the magnitude of the centripetal force acting on the car?*Hint: Break [math: FN] into components

A 917.4 kg car is driving in a roundabout on a frictionless banked track as shown in the diagram below.The angle of banking, [math: θ=16.2∘].What is the magnitude of the centripetal force acting on the car?*Hint: Break [math: FN] into components

A 965.8 kg car is driving in a roundabout on a frictionless banked track as shown in the diagram below.The angle of banking, [math: θ=14.8∘].What is the magnitude of the centripetal force acting on the car?*Hint: Break [math: FN] into components

A student ties a rock to a string then spins the rock in a vertical circular motion at constant speed. The tension in the string:

A man is moving in a horizontal circular motion in the air. The man is tied by a rope that is angled at 300 to the vertical. The rope provides ..

A banked curve is safer than a flat curve because ...

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单