问题 问答题

如图所示,为一平抛物体运动的闪光照片示意图,照片与实际大小相比缩小10倍.对照片中小球位置进行测量得:1与4闪光点竖直距离为1.5cm,4与7闪光点竖直距离为2.5cm,各闪光点之间水平距离均为0.5cm.则

(1)小球抛出时的速度大小为______m/s.

(2)小球抛出点______(填“在”或“不在”)闪光点1处,若不在,则抛出点距闪光点1的实际竖直距离是______cm.(空气阻力不计,g=10m/s2

答案

(1)在竖直方向上△y=gT2,T=

△y
g
=
(0.025-0.015)×10
10
=0.1s.所以两个点之间的时间间隔为:t=
T
3
=
1
30
S

则小球平抛运动的初速度v0=

x
t
=
0.05
1
30
m/s=1.5m/s.

   (2)A点在竖直方向上的分速度v4y=

y17
2T
=2m/s,则运动的时间t=
v4y
g
=0.2s.

竖直方向上的位移y=

1
2
gt2=0.2m>0.15m

所以小球的抛出点不在1点,则抛出点距闪光点1的实际竖直距离是0.2-0.15m=0.05m=5cm

故答案为:(1)1.5;(2)不在    5

阅读理解

Hee-haw! Scores of farms across the country are opening up to overnight guests. The best have all the appeal of a first-rate inn ----- plus here a moo, there a moo.

Sure, you and your kids plan to conquer the theme parks. In the meanwhile, why not make a little hay? Farm stays are fast becoming the great American alternative to the pre-packaged vacation.

LIBERTY HILL FARM

Rochester, Vt.; 802/767-3926; www.libertyhillfarm.com. Adults$75, teens $50,kids 12 and under $35, including breakfast and dinner; shared baths.

Beth and Bob Kennett run a farm straight out of a storybook. You’ll find Beth in the kitchen, rolling out dough(生面团) for a pie. Bob’s busy with other work. Guests sleep in seven sunny bedrooms right in the farmhouse and can participate in any of the farm jobs. Maybe you and your kids won’t be up at 6 a.m. to meet the milk truck, but you can help with the milking twice a day, collect eggs, and pick sweet corn and wild blackberries in season.

HULL-O FARM

Durham, N.Y.; 518/239-6950; www.hull-o.com; Adults $110, kids 10—14 $60, 5—9 $50, 2—4 $35, under 2 free, including breakfast and dinner; private baths.

It started in 1993 as a way to bring in some extra money at a time of falling milk prices. But soon after Frank and Sherry Hull opened their Catskill Mountains dairy farm to overnight visitors, they discovered they loved it. As you drive up, Sherry greets you on the porch(入口处)of the 1825 farmhouse with a cow-shaped cookie jar. Before long your kids are playing around with the cows, sheep, ducks, goats and getting ready for a hayride(乘坐装满干草的牛车出游).

MERAMEC FARM CABINS

Bourbon, Mo.; 573/732-4765; http://www.wine-mo.com Doubles with private bath $75, $10 per additional person. Trail and riding fees extra.

Climb onto the back of the Ford pickup and catch up with the herd. One gentle cow named Cricket will even let the kids sit on her back. At the barn(牲口棚), Carol will introduce you to the horses ---15 Missouri Fox Trotters --- and lead you on a trail ride over the hills and down along the spring-fed Meramec River, where everyone swims. Grab a fishing pole and head back to the river. When you have your fill of the wild, try Carol and Dave’s favorite restaurants or wineries(酿酒厂), within 20 miles of the farm.

小题1:The underlined sentence in the first paragraph implies that ___________.

A.you can enjoy the best cuisine at the first rate restaurant

B.some farm provide country experiences as well as good accommodations

C.farm work is hard, but you can enjoy it a lot, playing with the animals

D.if you want to hear a cow’s cry, please stay on a best farm小题2:We can learn from the three ads that _____________.

A.Hull-O Farm was not built for overnight visitors

B.Frank and Sherry Hull run a farm out of a storybook

C.kids can sit on a gentle cow’s back on Hull-O Farm

D.you can’t milk a cow if you get up late on Liberty Hill Farm小题3: The Browns have a 13-year-old son and 11-year-old daughter. If they stay on Liberty Hill Farm for one night, how much will they pay?

A.$175.

B.$220.

C.$235.

D.$250.小题4:Who will be most likely interested in the webpage?

A.Kids who want to find pleasure in the theme parks.

B.People who expect to be employed on the farm.

C.Researchers who are interested in raising cows on farms.

D.Those who plan to have family vacations on working farms.

单项选择题 A1/A2型题