【題目】下列關(guān)于“驗證機械能守恒定律”實驗的實驗誤差的說法，正確的是（ ）

A．重物質(zhì)量的稱量不準(zhǔn)會造成較大誤差

B．重物質(zhì)量選用得大些，有利于減小誤差

C．重物質(zhì)量選用得較小些，有利于減小誤差

D．打點計時器選用電磁打點計時器比電火花計時器誤差要小

【答案】B

【解析】為減小實驗誤差，重物應(yīng)選質(zhì)量大些的，且重物質(zhì)量不需稱量，A、C錯，B正確；電磁打點計時器的振針與紙帶間有摩擦，電火花計時器對紙帶的阻力較小，故選用電磁打點計時器誤差大些，D錯誤．

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