问题 实验题

小刚同学为了测量某种品牌牛奶的密度,用天平、 玻璃杯、量筒等器材,设计了如下实验步骤。

①用天平称出玻璃杯的质量m1

②将适量的牛奶倒入玻璃杯中;

③用天平称出玻璃杯和牛奶的总质量m2

④将杯中牛奶倒入量筒中,测出量筒中牛奶的体积V;

⑤计算牛奶的密度ρ。

(1)写出该实验测出的牛奶的密度的表达式ρ=_____________;

(2)为了减小测量牛奶体积的误差,可以通过调整该实验的步骤顺序来实现,试写出调整后的实验步骤顺序:_____________。

答案

(1)

(2)②③④①⑤

多项选择题
阅读理解

Ways to Burn More Calories

Run through water

Running in water is one of the toughest activities you can perform because the wet stuff is about 12 to 15 times as resistant (具有阻力的) as air. Try your hardest to run and you can burn about 17 calories per minute.

Start fast

Don’t be fooled — slow and steady won’t win the race. A recent study found that after a short warm-up, cyclists who rode hard during the first half of their workouts and then slowed for the second half burned about 10 percent more calories than those who started slow and finished fast.

Take to the sand

Here is some easy-to-remember advice on burning calories: the softer the surface, the more you burn. By walking or running on the beach, you can use up 20 to 50 percent more calories than you do going at the same pace on a hard trail.

Shut up and dance

Here’s the perfect excuse to sign up for that hip-hop dance class you’ve been eager to try. Surprising your body with new activities — dance, a new sport, you name it — forces it to work harder because it’s doing unfamiliar movements and using muscle groups in different ways.

Use your arms

Getting both your upper and lower body involved can provide a big calorie-burning advantage. So if you’re short of time or want to get everything you can out of your usual 45-minute workout, try total-body activities such as rowing ormming. You can evenng your arms as hard as you can while you walk.

小题1: How can water help you burn more calories?

A.By pushing your body.

B.By wetting your clothes and shoes.

C.By forcing you to run faster.

D.By forcing your body to work harder.小题2:What does “it” in Part 4 refer to?

A.Dance.

B.Movement.

C.Body.

D.Muscle.小题3:Which of the following statements is TRUE?

A.One can burn more calories when walking on the sand than on land.

B.One can burn more calories when walking on stones than on earth.

C.One can burn more calories when running in water than on the sand.

D.One can burn more calories when exercising using the upper body than using the lower body.