Question

几个物理问题 谢谢帮忙 灰常感谢

1. When a ball is dropped which of the following is true?
a. Kinetic energy is converted into potential energy.
b. Potential energy is converted kinetic energy.
c. Potential energy remains constant.
d. Kinetic energy remains constant.
2. Two cars with the same mass, and traveling at the same speed are in a head on collision. The first car suffer very little damage, while the front end of the second car is completely crumpled. Which car would have been more likely to injure the passengers?
a. The car with the crumpled front end would have more likely injured the passengers.
b. The passengers in each car would both have the same chance of injury.
c. The car with little damage would have more likely injured the passengers.
3.The airbag in a car works in a collision by . . .
a. increasing the time of the impact to the person.
b. reducing the impulse to the person.
c. reducing the momentum of the person.
d. increasing the force on the person.
4.What is the force that causes a helium balloon to rise?
a. The Bernoulli Force.
b. The Buoyant Force.
c. The Magdeburg Force.

Answer 1

1题B 势能转化为动能（ b. Potential energy is converted kinetic energy. ）
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2题单从物理角度看待，应该选 C 轻微受损的车让乘客受伤可能性更大
（c. The car with little damage would have more likely injured the passengers）
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3题A 增加对人的作用时间（a. increasing the time of the impact to the person. ）
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4题B 浮力（ b. The Buoyant Force.）

Answer 2

1，b，即势能转化为动能
2，c，变形严重的汽车会吸收更多的能量，则会有较少的能量作用到乘客身上
3，a，气囊的作用是增加做功的时间，当冲量一定时，时间越长，作用到人身上的力也越小，受到的伤害也会降低
4，c，氦气球上升是受到大气压力的作用