A mountain climber encounters a crevasse in an ice field. The opposite side of the crevasse is a height h lower, and is separated horizontally by a distance w. To cross the crevasse, the climber gets a running start and jumps in the horizontal direction. If the height of the crevasse increases but the width remains the same, then,

A) the minimum speed needed to cross the crevasse increases.

B) the minimum speed needed to cross the crevasse decreases.

C) the minimum speed needed to cross the crevasse stays the same

D) the minimum speed needed to cross the crevasse will depend on the mass of the mountain climber.

E) the minimum speed needed to cross the crevasse will depend on the weight of the mountain climber.

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. When they reach the lake below,

A) the splashdown speed of James is larger than that of John.

B) the splashdown speed of John is larger than that of James.

C) they will both have the same splashdown speed.

D) the splashdown speed of James will always be 9.8 m/s larger than that of John.

E) the splashdown speed of John will always be 25 m/s larger than that of John.

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below.

A) James reaches the surface of the lake first.

B) John reaches the surface of the lake first.

C) James and John will reach the surface of the lake at the same time.

D) Cannot be determined without knowing the mass of both James and John.

E) Cannot be determined without knowing the weight of both James and John.

A pilot drops a bomb from a plane flying horizontally at a constant speed. Neglecting air resistance, when the bomb hits the ground the horizontal location of the plane will

A) be behind the bomb.

B) be over the bomb.

C) be in front of the bomb.

D) depend of the speed of the plane when the bomb was released.

E) depend of the mass of the bomb when it was released.

**EXPERT ANSWER**

A mountain climber encounters a crevasse in an ice field. The opposite side of the crevasse is a height h lower, and is separated horizontally by a distance w. To cross the crevasse, the climber gets a running start and jumps in the horizontal direction. If the height of the crevasse increases but the width remains the same, then,

A) the minimum speed needed to cross the crevasse increases.

B) the minimum speed needed to cross the crevasse decreases.

C) the minimum speed needed to cross the crevasse stays the same

D) the minimum speed needed to cross the crevasse will depend on the mass of the mountain climber.

E) the minimum speed needed to cross the crevasse will depend on the weight of the mountain climber.

**Answer :**B) the minimum speed needed to cross the crevasse decreases.

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. When they reach the lake below,

A) the splashdown speed of James is larger than that of John.

B) the splashdown speed of John is larger than that of James.

C) they will both have the same splashdown speed.

D) the splashdown speed of James will always be 9.8 m/s larger than that of John.

E) the splashdown speed of John will always be 25 m/s larger than that of John.

**Answer :**B) the splashdown speed of John is larger than that of James.

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below.

A) James reaches the surface of the lake first.

B) John reaches the surface of the lake first.

C) James and John will reach the surface of the lake at the same time.

D) Cannot be determined without knowing the mass of both James and John.

E) Cannot be determined without knowing the weight of both James and John.

**Answer :**C) James and John will reach the surface of the lake at the same time.

A pilot drops a bomb from a plane flying horizontally at a constant speed. Neglecting air resistance, when the bomb hits the ground the horizontal location of the plane will

A) be behind the bomb.

B) be over the bomb.

C) be in front of the bomb.

D) depend of the speed of the plane when the bomb was released.

E) depend of the mass of the bomb when it was released.

**Answer : **B) be over the bomb.

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